Zone valve question

Old 11-25-09, 02:45 PM
Thread Starter
Join Date: Nov 2009
Location: New Jersey
Posts: 11
Upvotes: 0
Received 0 Upvotes on 0 Posts
Zone valve question


I just bought a house (first time home buyer ) that has an oil burner with associated baseboard heating. I noticed today that the temperature of the house never gets below 68 F, even when the themostat is set to 58 (yes, it is cold out side and I do not have AC :-). I looked at the hemostat and it seemed that the mercury switch and the bimetallic strip were in good order. The baseboards were warm though. So I go and check the furnace/boiler unit and noticed that there is a honeywell zone valve that is not wired to anything and is set to manual. The house only has one zone (it is a small house :-)).

This has lead me to a numbe of questions:

Is a zone valve necessary for fuel efficiency in a one zone home?

I suspect that the residual heating is coming from convection since the zone valve is never closing, right? So, is it easy to wire up the valve? I like a house that is cooler than 68F.


Last edited by Milo2112; 11-25-09 at 03:08 PM.
Old 11-25-09, 03:59 PM
NJT's Avatar
NJT is offline
Join Date: Oct 2006
Location: USA
Posts: 19,710
Upvotes: 0
Received 8 Upvotes on 6 Posts
I'd say your thinking is on the right track, but I wouldn't call it 'convection' exactly... while it is true that the baseboards do heat mostly by convection, the reason they are heating at all is likely because of 'thermo-siphon', or 'gravity flow'... where the more bouyant hot water from the boiler 'floats' up into the system, pushing the cold water that's in the system back into the boiler. This cycle will continue as long as the boiler is warmer than the water in the system.

Without seeing the system though, this is guesswork... so don't take it as gospel.

The zone valve won't _directly_ affect the efficiency of the system, but what it can help with is reducing the 'standby losses' in your system. It will tend to keep the heat that you don't want/need in the house in the boiler. You will still lose some of that heat up the chimney though...

A zone valve can stop the gravity flow... but so can a properly installed 'flow check valve' and that won't take any electricity, but it will take some plumbing skills to install.

With any luck, it may be an easy matter to wire the zone valve (IF it's functional) and it might do the trick.

Can you take pics of the system? if so, free account / Image hosting, free photo sharing & video sharing at Photobucket / upload there and drop a link to the album here for us to view. Try to get the piping around the boiler and take a few from far enough back that we can see how it all fits together...

Tell us make/model of the boiler, and if possible, the make/model of AQUASTAT on the boiler. The aquastat is probably a gray metal box about 4x6" on the front/side of the boiler.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: