remote manifolds but no end switch to mechanical room

joseph annon

Just went to a home with a call for no heat. The boiler was on standby mode. I checked out the heat call connection and located the single zone valve that has the end switch connected to the boiler. The zone valve motor had failed leaving the house with no heat. There are nine other thermostats connected to zone valves in remote manifolds. The issue is that the other nine zones do not signal the boiler to run.
I have thinking of options to rectify the situation. The house is slab on grade and no attic space. Running an end switch entails three roof penetrations and conduit on a flat roof.

Is there a wireless switch that can be installed? I have looked a bit on the internet but not sure that I am using the correct terms to find what I would need.

It is a Lochinvar Knight boiler so it is possible to run the boiler on outdoor reset and it will shut down when it warms up. I would need to change the system pump to a Delta P pumping system.

Are there other options?

I think a Grundfos Alpha pump may be the best bet with boiler jumped into heat mode with an outdoor reset and outdoor reset curve.

Jamie Hall

Not a particularly elegant solution, and not as efficient as it might be -- but if you use a delta P pump, it should ramp up the flow when a zone valve opens somewhere out in the wilderness. You will, however, need balancing valves on the lines to the various manifolds to ensure that the ones with the lower natural head loss don't hog the flow.

hot_rod

Delta P circulators were designed for applications like yours.
I’d guess most of the world of hydronics heats with panel radiators. As non electric TRVs open and close the circulator responds accordingly. The same concept applies to your system.
Either ODR or a centrally located t-stat for winter/ summer switch on.

EdTheHeaterMan

I'm guessing that the system worked fine prior to the zone valve failure. Are you sure that you need to fix something that is not broke?

My first question to the homeowner is "How well did the system work before this problem happened?"
"Were all the different rooms comfortable?" Were there any rooms that were particularly cold?" Were there any rooms that were particularly hot?"

If you get NO to all the above questions, Then don't try to fix it. It ain't broke.

On the other hand, If there are problems with the design, then we can certainly help with answering your query.

hot_rod

Nine zone valves that all come on with a single thermostat call? May as well lock them open? Let the single thermostat turn on the circulator.

tim smith

functional devices probably has a wireless transmitter and relay. contact closure on transmitter would send signal to zone valve to turn on. The closure would be via end switches on telestats. all 24v. Look & see.
Good luck
Tim

tim smith

another option
https://relaypros.com/Relay/Relay/wireless_contact_closure

pedmec

You answered your own question, lol. you can put one zone on a three way so at minimum flow there is always a bypass for it.

Derheatmeister

Uponor was just what you need..

EBEBRATT-Ed

I beleive the OP said he has 9 other stats and 9 other zone valves

hot_rod

Some examples of how a ∆P circulator works with zoned systems.

joseph annon

Ed the heater man.
One small detail I forgot to mention is the home is slab on grab in floor radiant. Most of the house has bricks on the slab except for the kitchen which is wood on the slab.

Ed The Heater Man
There are issues with the heat in the Kitchen. To the point that there is a mini split installed to heat the kitchen area. There is also a separate guest house on this same heating system that I omitted mentioning. I didn't go in there. The house is a vacation home and not used often so when the owners are going the visit a few days before the heat is moved from 60*F to 72*F.The thermostat that is controlling the whole system is in a little used bedroom. That bedroom has the second highest heat loss in the house. Due to 2 exterior walls with windows and one wall next to the garage which is not heated. The kitchen has two exterior walls with north wall having large sliding glass doors to the north and large window to the east. And an open fire place. (no doors to seal it. probably has a damper but I do not know if the damper is used.

Hot Rod. Thank you for the screen shots are helpful reading.

Tim Smith The controls are mostly Caleffi three wire telestats with nothing wired to the end switch of the telestat.

pedmec I thought I was on the right track and I find it helpful to put it out there to see if I am missing something.