Wiring a Heat Exchanger and Modine and Pump.

hotblast1357 · Post by **hotblast1357** » Wed. Aug. 26, 2015 5:11 am

http://www.supplyhouse.com/Honeywell-R845A1030-Sw ... -4122000-p

Is this what we are looking for?

hotblast1357 · Post by **hotblast1357** » Wed. Aug. 26, 2015 5:38 am

If I have a call for heat with the modine, will the power to the pump back feed to the oil furnace fan side and power it also?

McGiever · Post by **McGiever** » Thu. Aug. 27, 2015 5:50 pm

Aren't you using the zone valves?

Zone valves can have "end switch" to operate the relay. But you want one dpst relay box per one zone.

Each relay will start the same pump on 1st pole and at the same time start the fan on the 2nd pole of that relay.

So , no, each fan has a separate contol relay and only that one fan will switch on for that one t'stat/relay/zone.

Those relays you showed are okay.

hotblast1357 · Post by **hotblast1357** » Thu. Aug. 27, 2015 7:06 pm

No I am not using zone valves, just one pump.

McGiever · Post by **McGiever** » Thu. Aug. 27, 2015 8:19 pm

hotblast1357 wrote:No I am not using zone valves, just one pump.

Two different t'stats one pump.
One pump two different fan coils...hmmm.

Need to make both t'stats work the one common relay for that pump.
Then use two "strap on" aquastats, one on each of the fan coils. They must close on temp rise to start and stop the fan motors.

Scottscoaled · Post by **Scottscoaled** » Thu. Aug. 27, 2015 8:27 pm

Two of those will work just fine

Set both next to pump/boiler. A 14-2 and a thermostat wire will handle the Modine. The air handler,,, will take care of itself with a pair.

hotblast1357 · Post by **hotblast1357** » Fri. Aug. 28, 2015 5:24 am

McGiever wrote:
hotblast1357 wrote:No I am not using zone valves, just one pump.
Two different t'stats one pump.
One pump two different fan coils...hmmm.

Need to make both t'stats work the one common relay for that pump.
Then use two "strap on" aquastats, one on each of the fan coils. They must close on temp rise to start and stop the fan motors.

So what your saying is control the coil by the pump? When a t'stat calls it will kick the pump on, which will warm the pipes, allowing the snap disc or aquastat to make connection turning the fan on? How do I control the individual aquastat? Run the t'stat through it so even if the pipe is warm it has to see a sense from the t'stat?

hotblast1357 · Post by **hotblast1357** » Fri. Aug. 28, 2015 5:25 am

Scottscoaled wrote:Two of those will work just fine Set both next to pump/boiler. A 14-2 and a thermostat wire will handle the Modine. The air handler,,, will take care of itself with a pair.

Scott, two of what will work fine? Aquastats?

The air handle will take of itself with a pair of what?

Sorry it's early lol

McGiever · Post by **McGiever** » Fri. Aug. 28, 2015 11:57 am

Apologies, that will not work for you.

Use Scott's way.

McGiever wrote:
hotblast1357 wrote:No I am not using zone valves, just one pump.
Two different t'stats one pump.
One pump two different fan coils...hmmm.

Need to make both t'stats work the one common relay for that pump.
Then use two "strap on" aquastats, one on each of the fan coils. They must close on temp rise to start and stop the fan motors.

hotblast1357 · Post by **hotblast1357** » Fri. Aug. 28, 2015 6:39 pm

So what is Scott's way? Lol

McGiever · Post by **McGiever** » Fri. Aug. 28, 2015 7:53 pm

Two relay boxes, one relay box gets 14-2 romex type NM and a 1/ pair 24v t'stat to modine. Fan power 120v and 24v to operate relay back at pump for relay coil for start of pump.
Second relay box gets 1/ pair 24v t'stat only, run to oil furnace fan for existing fan relay already there. And also must start local pump.

hotblast1357 · Post by **hotblast1357** » Sat. Aug. 29, 2015 5:09 am

Ok let me ask ou this, I already ran 14-3 out to the modine from the dump zone aquastat, I just didn't use the ground cuz it's only two wires, that makes connection out at the modine for the fan to power, is there a way I can just tie into that from the relay instead of running another power wire out there?

Scottscoaled · Post by **Scottscoaled** » Sat. Aug. 29, 2015 7:26 am

Dump zone will go across TT for that "zone". Just like the T-stat. NO POWER.

McGiever · Post by **McGiever** » Sat. Aug. 29, 2015 7:50 am

You must use 2 relay boxes, 1 per zone. Each t'stats pull in the appropriate magnetic coil.

Each relay will start the same pump on 1st pole/set of contacts and at the same time start the the appropriate fan on the 2nd pole/set of contacts of that relay.

So , no backfeed, each fan (2) has a separate contol relay and only that one fan will switch on for that one t'stat/relay/zone.

As Scottscoaled is saying...in order to use the modine as a dump you only need the dump zone a'stat to wire parallel (24v) with the modines 24v t'stat wires at the modine's relay box magnetic coil...no addition wire needs ran to the garage...it is done with extra/parallel 24v control at the relay box and the relay will use the same existing 120v wire for power out to the fan.

Scottscoaled · Post by **Scottscoaled** » Sat. Aug. 29, 2015 10:42 am

You could get it done with one phone call.