Hello,

I've spent the last 2-3 hours reading threads on this forum and attempting to troubleshoot a lack of heat in one of my three zones. There's a lot of information on here, and through reading other posts, I've tried to learn the basics of my heating system and do a few basic troubleshooting steps but am not sure what to do next. Maybe some of the helpful and knowledgeable posters here can help or at least point me in the right direction:

Basic Setup:
Natural Gas Boiler (hot water) with three heat zones. Each Zone has a Taco 007-F3 circulator. Heat is fine on the upstairs and downstairs zone, but the third zone is a den that hangs off the side of the house - no heat there.
There's, one other detail to mention. I only have one switch relay in my entire setup. There's a sr501 One Zone switching relay is Labeled "Den". The other two zones don't seem to have an equivalant piece of hardware, which confuses me slightly. It looks like the previous owner of the house added this zone and the switch relay after the initial installation of the boiler. For the other two zones, the wiring from the thermostats appear to terminate in the boiler itself. The den is the zone that has the heat problem.

Tried the following:
1) Changed batteries in the thermostat.
2) Attempted to feel if the circulator is running, but it's hard to tell if it is or not. Circulator is installed on the outflow (hot) side of the boiler. Pipes to this zone leading away from the circulator are not very hot.
3) Blead water out of the valves on the two baseboard heaters in the den. Didn't seem like there was any air in there.
4) When I look at the sr501 One Zone switching relay Labeled "Den". The Power light is on, but the Zone1 light is not illumintated when I turn heat on the thermostat. Seems like this is the problem, so I'd guess that the issue is either the switch relay or the thermostat.
5) I removed the thermostat facing and used a wire to bridge the two connections that the thermostat manual suggests. And, Viola!, the Zone1 light comes on on my switching relay, but 30 minutes later, and the baseboards in my den haven't started to heat up.
6) all other diagnostics for the boiler seem to be ok. PSI is about 22 psi, water temp on the gauge is close to boiling, and I'm getting heat on the other two zones.

What to try next?

Thanks
Matt

 

When you jumpered the tstat, you may have found the 'trouble'.. but the rest might be design issue (that den zone setup). What was the temp of the boiler when you tried that test ?
Sounds like your first 2 zones control the boiler (via the TT connectors at the boiler) and the boiler then controls the circ pumps). The den zone's pump just runs when its tstat calls, regardless of the boiler's temp.
You could try cranking one of the other tstats up high, while leaving that den tstat jumpered. The boiler should come up to temp .. then see if your pipe heading to the den warms up.

 

Thanks, I'll try that when I get home from work tonight and report back on the results. I suspect you are right about the zone for the den being a poor design from the start. The boiler did cycle on at least once to heat the other zones while I had the tstat jumpered, and it didn't seem like the pipes leading to the Den got as hot as I was expected. It was already getting late last night when i figured out to jumper the thermostat, so I just might not have been patient enough.

Thanks again,
Matt

 

Problem Solved!

Thanks, I jumpered the Tstat in the Den and cranked up the heat on the first floor and the baseboards did indeed get hot. DaveC72, thanks for your input!

Matt

Beer 4U2

 

If you can live with the variable heat supply in the den, I guess it could be end of story.

If you want to tie in that den zone so that it calls the boiler like the other zones do, then there's more work to do..

I think the only drawback to the existing system (once you replace that den tstat), is that the temp swings will be larger than optimum for the den. In a cold snap, certainly one of the other zones will call (and heat the boiler).. the den will probably be calling by then and will finally get some heat.

Id be curious if the other 2 zone circ pumps are simply wired in parallel to the aquastat/controller on the boiler (so that either of the other 2 zone's tstat calls, it starts both zones heating..).

Increased comfort might be in your future..

 

Spilima,
It sounds like you might have a wiring problem from you sr501 to the boiler. You have a taco switching relay that turns on the pump and well as the boiler on a call for heat. Your wiring should be as follows:
N H 3 4no 4nc 5no 5nc 6
N is neutral, H is hot, 3 is jumpered from H, Circ goes to 4no and N, t-stat wire goes from 5no and 6 to TT on boiler control and it should work. Your t-stat from the room goes to TT on your sr501. N and H are your outside power.(120V). If they didn't run wire from 5 and 6 to boiler it will not come on to reheat water and you'll just circulate cold water.
Type in sr501 switching relay in your search and you can see.

 

spot8, if he did hook the relay up to the boiler TT, wouldnt all 3 pumps run when the den calls ?

From the first post, the other 2 zone's stats wire directly to the TT at the boiler (no relay).. Im assuming both of those other zones circ pumps are parallel wired to the circ pump terminals at the boiler also (but we do need some pics or diagram to be sure).
Im wondering if the other 2 zones supply heat when either stat calls.. crazy setup.

Hopefully he stops back in, so we can help make that house more comfortable.

 

Dave,
The other zones would not run. The tt on the boiler is only there to turn the boiler on when the water temp. gets low. The sr501 is what controls the zone. The t-stat in the room is connected to the 501 which activates the pump which sends hot water to the zone. The tt from the 501 to the boiler is only activated on a call from the aquastat to reheat the water. If wired correctly they should all work independently.

 

spot, I think you might be missing Dave's point... from this description by the OP:

It sounds as though the other two zone circs are running off some unknown source... MAYBE wired in parallel to C1/C2 on the aquastat.

And IF that is so, then wiring the 501 to also call the boiler will result in all three zones getting heat simultaneously.

If this is true, I would think the best solution for OP would be to purchase an SR 503/4, get rid of the 501 and consolidate the pump and t'stat wiring into one panel... OR add individual relays to the other two zones... which would cost more.

I hope Matt comes back to clarify... cuz that setup don't sound right to me.

 

Spilma
If the other pumps are not wired correctly you could have a problem as NJ stated but if that's the case my suggestion would be this. Your boiler control came with the proper tereminals for one circ.(C1/C2). To proerly run other pump off of that control you need two more terminals.(ZC/ZR). If those terminals are not there or were not used Trooper and Dave are correct. If you have those you can get one more 501 and wire properly and be fine. What model aqustat relay on your boiler and do you have those terminals.