Cycling circulator to avert frozen pipes?
First time posting here, want to say thanks, as the forum is great, and the short amount of time I have spent here has been awesome.
Ok, so I am an electrician and one of my contractors is having an issue. One of the three heating zones his guys installed was on a raised cape and in a crawlspace, and you guessed it...pipes are freezing to the upstairs zone.
I haven't looked into relay panels as of yet, but was gonna send out some feelers to see if there's a "ready made" situation to the problem via tstat bulb in the area, and running a dual zone tstat?
Would it make sense for me to do that, or can it be done using a timer downstairs? In my opinion if there's a 365day timer I can employ to simply cycle that particular circulator for lets say..20mins on the hours when the OAT is low enough to endanger freezing. Even without. The hierarchy in my head would be
Timer> -OAT sensor, wireless sensor, no sensor- > circulator (line side or load side depending on if a relay exists where lets say. the temp in the room can open my "closed" timer circuit to avoid the room becoming too warm that the zone supplies outside of this freezing crawlspace.
-to my knowledge they have tried insulating the supply pipes, and my contractor has called on me for a possible solution.
Hope that wasn't explained too terribly, and if any clarification is needed I can help. I appreciate any input. Thanks guys!
Propylene glycol or a freeze stat
Is there a control valve (what voltage), how is it piped (bypass loop or not)? The first thing I would consider is a dry bulb stat which could be wired to energize a relay to turn the pump on (or open the valve) on a drop in temp. This way no timers are needed and everything is self-contained in the area you are concerned with.
Self regulating heat tape and some pipe insulation would be better then nothing and its simple as mud.
I would still though very seriously consider adding glycol to that system due to the fact that whatever it is you do, it will fail and freeze causing major damage to the structure. One lengthy power outage for example and it's all over.
Seal up crawlspace, insulate crawlspace. Add a little heat to it, and no more pipe freezing.