The Switching Relay
heating system. Zone 1 has optional priority over zones 2 through 4 and can be used to provide heat to an indirect
domestic hot water tank. The 304P includes optional exercising to prevent circulator seizure when not in use, and optional
post purge operation of the last operating zone to maximize energy savings. The 304P provides a RoomResponseTM
signal to modulating-condensing boilers to optimize comfort while improving boiler efficiency.
304
P connects up to four thermostats and operates circulators to provide heating to a zoned hydronic
Features
• RoomResponseTM signal
• Compatible with all low voltage thermostats
• Unlimited zone expansion
• Zone priority
• Priority override
• Pump exercising
• Post purge
•
LED for each zone, priority, end switch and RoomResponse
User Interface ....................................................................7
Indicator LED ................................................................. 7
Sequence of Operation .....................................................7
Technical Data ..................................................................12
Limited Warranty and Product Return Procedure ............12
Important Safety Information
It is your responsibility to ensure that this control is safely installed according to all applicable codes and standards. tekmar is
not responsible for damages resulting from improper installation and/or maintenance.
This is a safety-alert symbol. The safety alert symbol is shown alone or used with a signal word (DANGER,
WARNING, or CAUTION), a pictorial and/or a safety message to identify hazards. When you see this symbol
alone or with a signal word on your equipment or in this manual, be alert to the potential for death or serious
personal injury.
This pictorial alerts you to electricity, electrocution, and shock hazards.
This symbol identifies hazards which, if not avoided, could result in death or serious injury.
This symbol identifies hazards which, if not avoided, could result in minor or moderate injury.
This symbol identifies practices, actions, or failure to act which could result in property damage or damage to
the equipment.
Read manual and all product labels BEFORE using the equipment. Do not use unless you know
the safe and proper operation of this equipment. Keep this manual available for easy access by all
users. Replacement manuals are available at tekmarControls.com
•
It is the installer’s responsibility to ensure that this control is safely installed according to all applicable codes and
standards.
•
Improper installation and operation of this control could result in damage to the equipment and possibly even personal
injury or death.
• This control is not intended for use as a primary limit control. Other controls that are intended and certified as safety limits
must be placed into the control circuit.
The control includes fuses and transformer that are serviceable. Do not attempt to service any other parts on the control.
Attempting to service the control voids the warranty.
• Strip all wiring to a length of 3/8 in. or 10 mm for all terminals.
• A circuit breaker or power disconnect that provides power to the control should be located nearby and clearly labeled.
• Refer to the current and voltage ratings at the back of this manual before connecting devices to this control.
The installer must ensure that this control and its wiring are
isolated and/or shielded from strong sources of electromagnetic
noise. Conversely, this Class B digital apparatus complies
with Part 15 of the FCC Rules and meets all requirements of
the Canadian Interference-Causing Equipment Regulations.
However, if this control does cause harmful interference to
radio or television reception, which is determined by turning
the control off and on, the user is encouraged to try to correct
the interference by re-orientating or relocating the receiving
antenna, relocating the receiver with respect to this control,
and/or connecting the control to a different circuit from that
to which the receiver is connected.
Cet appareil numérique de la classe B respecte toutes les exigences du Règlement sur le matériel brouilleur du Canada.
• Needle-nose pliers
• Wire stripper
• Four 1/8" - 1" wood screws
• 1 Installation and Operation Manual 304P_D
Location
• Keep the control dry. Avoid potential leakage onto the control.
• Maintain relative humidity less than 90% in a non-condensing environment.
• Avoid exposure to extreme temperatures beyond 32-122°F (0-50°C).
• Install away from equipment, appliances, or other sources of electrical interference.
• Install to allow easy access for wiring, viewing, and adjusting the display screen.
• Install approximately 5 feet (1.5 m) off the finished floor.
• Locate the control near pumps if possible.
• Provide a solid backing which the enclosure can be mounted to. Example: plywood or wall studs.
• Use the conduit knockouts provided on the upper, lower, and back of the enclosure for wiring.
Installing the Enclosure
To prevent the risk of personal injury and/or death, make sure power
is not applied to the control until it is fully installed and ready for final
testing. All work must be done with power to the circuit being worked
on turned off.
Please be aware local codes may require this control to be installed
or connected by an electrician.
The Switching Relay 304P operates the circulators for four heating zones when the corresponding thermostat calls for heat.
The boiler is fired whenever a zone calls for heat.
The Switching Relay 304P operates four heating zone circulators when the corresponding thermostat calls for heat. Zone 1
heats a domestic hot water tank. When priority is selected, zones 2 through 4 shut off when zone 1 is heating. The boiler is
fired when there is a call for heat.
A1 = DHW Tank Aquastat
B1 = Modulating Condensing Boiler
BP = Boiler Pump
P1 = Zone 1 DHW Tank Pump
P2 to P4 = Zone 2 through 4 Pump
T1 = WiFi Thermostat 561 or 562
T2 = Thermostat 518 or 519
T3 = Generic Bi-Metallic Strip Thermostat
Two Switching Relay 304P's operate eight heating zone circulators. The two controls are connected together using an expansion
bus wire. The master 304P fires the boiler when any zone calls for heat. If priority is selected, zones 2 through 8 shut off when
zone 1 is calling for heat.
A1 = DHW Tank Aquastat
B1 = Modulating Condensing Boiler
BP = Boiler Pump
P1 = Zone 1 DHW Tank Pump
P2 to P8 = Zone 2 through 8 Pump
B1
T1 to T3 = WiFi Thermostat 561 or 562
T4 to T5 = Thermostat 518 or 519
T6 = Generic Digital Power-Stealing Thermostat
T7 = Generic Bi-Metallic Strip Thermostat
Off when power disconnected or transformer fuse is blown.
•
Priority
• On when zone 1 has priority over zones 2 to 4.
RoomResponse
• On when modulating condensing boiler is operating below
maximum setting.
TM
Sequence of Operation
Zone Operation
When a thermostat calls for heat by closing the R and W
terminals:
• 115 V (ac) is applied to the corresponding circulator pump.
• The corresponding zone indicator LED is turned on.
Boiler Operation
When a thermostat calls for heat by closing the R and W
terminals:
• The boiler end switch XX is closed to fire the boiler.
The RoomResponseTM 0-10 V (dc) or 4-20 mA signal is sent
•
to a modulating-condensing boiler.
DHW Operation
Many modulating-condensing boilers have multiple temperature
call inputs. Wire the DHW end switch to input recommended
in the boiler's manual.
When a zone 1 calls for heat by closing the R and W terminals:
• The DHW end switch is closed to fire the boiler at the DHW
temperature.
• The Mod Boiler output is changed to 10 V (dc) or 20 mA.
Master / Member DIP Switch
•
Allows for unlimited expansion using additional Switching
Relays and/or Zone Valve Controls.
The Master Switching Relay is wired and operates the boiler.
•
• If using a single Switching Relay set to Master.
When using multiple Switching Relays and/or Zone Valve
•
Controls, set one control to Master and set all other controls to Member.
T-Stat 1 Priority DIP Switch
When T-Stat 1 is calling for heat by closing the R and W
terminals:
• 115 V (ac) is applied to the zone 1 circulator pump.
• Zone 1 indicator LED is turned on.
• Priority indicator LED is turned on.
• Zones 2 to 6 circulator pumps and LEDs are turned off.
• Expansion Member controls shut off their zones.
•
After 60 minutes of continuous zone 1 call for DHW heating,
zones 2 to 6 and all Expansion Member control zones are
able to turn back on. This prevents building freeze up if the
DHW tank aquastat fails in the closed position.
Exercising DIP Switch
ON: Each circulator pump is energized for 30 seconds every
72 hours.
OFF: Circulator pump exercising disabled.
Zone 1
• On when thermostat 1 calls for heat.
Zones 2 to 4
• On when the corresponding thermostat calls for heat.
• Off during priority operation.
• Off when corresponding thermostat stops calling for heat.
Post Purge DIP Switch
ON: After the last thermostat stops calling for heat, the last
circulator pump remains on for 2 minutes to purge heat from
the boiler to the zone.
OFF: Post purge disabled.
Mod Boiler DIP Switch
Select either 0-10 V (dc) or 4-20 mA signal to the modulating
condensing boiler. Consult the boiler manual to determine
the signal type. The DIP switch position does not matter if
the modulating boiler output is not used.
Fuses
• All fuses are T5A 250V slow blow.
• Fuses 1 to 4 correspond to the zone 1 to 4 circulator pump
output. If a fuse is blown, first check that the pump is not
seized and the wiring is not shorted. Then replace the fuse.
•
Fuse 7 and 8 correspond to the 24 V (ac) transformer power
supply. If a fuse is blown, first check that the thermostat
wiring is not shorted. Then replace the fuse.
Expansion Terminals
Connect the five wires of the expansion bus from the master
to the member controls.
The RoomResponseTM signal adjusts the temperature of a
modulating condensing boiler that accepts a 0-10 V(dc) or
4-20 mA input. It works by continually adjusting boiler water
temperatures to the lowest possible value to meet comfort
without wasting energy. This is done by monitoring each
thermostat's on and off time pattern and determines the ideal
water temperature for each zone. The control then chooses the
highest water temperature requirement of all the thermostats
and provides a 0-10 V (dc) or 4-20 mA signal proportional to
the boiler operating temperature. The RoomResponse
is a DOE compliant method of controlling boiler temperature
to building load. The RoomResponse
to on/off boilers.
Benefits of the RoomResponse
• Increase in boiler efficiency
• Reduction in room temperature swing
• Reduction in expansion noises from heating pipes
TM
signal is not available
TM
signal include:
TM
signal
Mod Max % Dial
The upper limit of the 0-10 V (dc) or 4 -20 mA signal to the
modulating condensing boiler can be set using the Mod Max
% Dial.
This sets the upper temperature limit for the boiler.
7080
9060
50100
MOD MAX %
Mod Max % dial set to 100% in the illustration.
The dial is only applicable to controls set as the Master.
Mod Max %Max VoltageMax mA
50512
60613.6
70715.2
80816.8
90918.4
1001020
Setting the Max Mod % Dial
Required Adapter
Boiler Make/Model
Aerco AM seriesNot required0-10 V50%65%80%100%
Bosch GreenstarICM Module0-10 V55%70%80%100%
Buderus GB142, GB162EM10 Module0-10 V50%60%75%90%
Burnham
Camus
HTP EliteNot required0-10 V50%65%80%90%
IBC VFC and SL series
Laars
Laars
Lochinvar
Lochinvar
NTI Trinity Fire Tube and LXNot required4-20 mA55%65%75%90%
Literature304P_C, 304P_D, 304_J
ControlMicroprocessor control. This is not a safety (limit) control.
Packaged weight5.0 lb. (2250 g)
Dimensions8-3/16" H x 10-12/18" W x 2-3/8" D (208 x 271 x 60 mm)
EnclosureCover: ABS plastic, Base: galvanized steel, NEMA type 1
Approvals
Ambient conditions32 to 122°F (0 to 50°C), ≤ 90% RH non-condensing
Power supply115 V (ac) ±10%, 60 Hz, 17.3 A
Transformer40 VA at 24 V (ac), expandable to 80 VA with additional transformer M3069 (sold separately)
Control load7 VA at 24 V (ac)
FusesT5A 250 V slow blow, two spare fuses included
Pump relays115V (ac), 5 A, 1/3 hp, 17.3 A combined
Boiler XX end switch24 V (ac), 5 A
DHW end switch24 V (ac), 5 A
Mod boiler output0-10 V (dc) 500 min impedance / 4-20 mA 1 k max impedance
CSA C US
Limited Warranty and Product Return Procedure
Limite d Warranty The liability of tekmar under this warranty is limited. The
Purchaser, by taking rec eipt of any tekm ar product (“Product”), acknowledges the terms of the Limited Warranty in effect at the time of such Product
sale and acknowledges that it has re ad and understands same.
The tekmar Limited Warranty to the Purchaser on the Products sold hereunder
is a manufacturer’s pass-through warranty which the Purchaser is authorized to
pass through to its customers. Under the Limited Warranty, each tekmar Product is warranted against defects in workmanship and materials if the Product
is installed and used in compliance with tekmar’s instructions, ordinary wear
and tear excepted. The pass-through warranty period is for a period of twenty-four (24) months from the production date if the Product is not installed during
that period, or twelve (12) months from the documented date of installation if
installed within twenty-four (24) months from the production date.
The liability of tekmar under the Limited Warranty shall be limited to, at tekmar’s
sole discretion: the cost of parts and labor provided by tekmar to repair defects in
materials and / or workmanship of the defective product; or to the exchange of the
defective product for a warranty replacement product; or to the granting of credit
limited to the original cost of the defective product, and such repair, exchange or
credit shall be the sole remedy available from tekmar, and, without limiting the
foregoing in any way, tekmar is not responsible, in contract, tort or strict product liability, for any other losses, c osts, expenses, inconveniences, or damages,
whether direct, indirect, special, secondary, incidental or consequential, arising
from ownership or use of the product, or from defects in workmanship or materials,
including any liabilit y for fundamental breach of contract.
The pass-through Limited Warrant y applies only to those defective Products
returned to tekmar during the warranty p eriod. This Limited Warranty does not
cover the cost of the parts or labor to remove or transport the defective Product, or
to reinstall the repaired or replacement Product, all such costs and expenses being
subjec t to Purchaser’s agreement and warranty with its customers.
Any representations or warranties about the Products made by Purchaser to its customers which are different from or in excess of the tek mar Limited Warranty are the
Purchaser’s sole responsibility and obligation. Purchaser shall indemnify and hold
tekmar harmless from and against any and all claims, liabilities and damages of any
kind or nature which arise out of or are related to any such representations or warranties by Purchaser to its customers.
The pass-through Limited Warrant y does not apply if the returned Product has been
damaged by negligence by persons other than tekmar, accident, fire, Act of God,
abuse or misuse; or has been damaged by modifications, alterations or attachments
made subsequent to purchase which have not been authorized by tekmar; or if the
Product was not installed in complianc e with tekmar’s instructions and / or the local
codes and ordinances; or if due to defective installation of the Product; or if the Product was not used in c ompliance with tekmar’s instructions.
THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR
IMPLIED, WHICH THE GOVERNING LAW ALLOWS PARTIES TO CONTRACTUALLY EXCLUDE, INCLUDING, WITHOUT LIMITATION, IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, DURABILITY OR DESCRIPTION OF THE PRODUCT, ITS NON-INFRINGEMENT OF
ANY RELEVANT PATENTS OR TRADEMARKS, AND ITS COMPLIANCE WITH
OR NON-VIOLATION OF ANY APPLICABLE ENVIRONMENTAL, HEALTH OR
SAFETY LEGISLATION; THE TERM OF ANY OTHER WARRANTY NOT HEREBY
CONTRACTUALLY EXCLUDED IS LIMITED SUCH THAT IT SHALL NOT EXTEND
BEYOND TWENTY-FOUR (24) MONTHS FROM THE PRODUCTION DATE, TO
THE EXTENT THAT SUCH LIMITATION IS ALLOWED BY THE GOVERNING LAW.
Product Warranty Return Procedure All Products that are believed to have
defects in workmanship or materials must be returned, together with a written
description of the defect, to the tekmar Representative assigned to the territory in
which such Product is located. If tekmar receives an inquiry from someone other
than a tekmar Representative, including an inquiry from Purchaser (if not a tekmar
Representative) or Purchaser’s customers, regarding a potential warranty claim,
tekmar’s sole obligation shall be to provide the address and other contact information regarding the appropriate Representative.
WARNING: This product contains chemicals known to the State of
California to cause cancer and birth defects or other reproductive harm.