Problem with oil burner (hot water baseboard)

Ibby14

My problem is with the top floor of my house, and I can't tell if it's the thermostat or the zone valve in the basement. The thermostat is a Honeywell 2 wire mercury. The heat will not go on in that zone. I took off the thermostat and put the wires together but still the heat will not go on unless I make sure the downstairs thermostat makes the furnace go on, then the upstairs heat will come on only very lightly, never fully, it's only warm and not for very long. I'm afraid of the temperature going down enough to freeze pipes, it's very cold outside. I tried putting the zone end switch to manual, and it did let hot water through but only when I turned the furnace on with the other zone thermostat. Anyone have any ideas what's going on? Could it be the thermostat and the zone valve? 

JStar

Heat

Could be any part of that control circuit. Are you able to check the wiring with a multimeter?

Ibby14

furnace

By control curcuit do you mean the zone control valve? I know a little (but just enough to get me in trouble) I'll have to work with it tomorrow and get by with electric heaters tonight, I have to leave for new years eve festivities, I'd rather work on the furnace (but I don't want to tick off the wife either). I'll check again tomorrow and let you know what happens. Thank you.

Steve Whitbeck

bad end switch

The zone valve has a bad end switch so it doesn't turn the boiler on.

What is the water pressure on the guage? It should be 12 PSI.

I bet it is very low and that is why you don't get much flow to the second floor.

You could also have a pump problem. Besides the end switch.

billtwocase

What Steve said

Pics will help, and zone valve brand/model. Could be low pressure, or air bound

Ibby14

furnace

The zone valve is a Honeywell F4 9819, and I have a Honeywell 2 wire heat only mercury thermostat. The problem zone valve is on the left. I have the end switch on manual so the problem zone heats up every time the other zone heat comes on, and I can now say that left to it's own devices it does keep the problem zone sufficiently heated. After leaving it on for a sufficient amount of time I found that the only reason it wasn't fully heating was that I had the other zone set very low because I kept electric heaters on, so the furnace was rarely turning on in the non problem zone so the problem zone was rarely receiving hot water. Of course it still won't follow what I set on the thermostat. Are we still looking at a bad zone valve? Did I make any sense? Thanks.

Ibby14

mistake

billtwocase

zone valve

put the lever back on automatic, and turn up the thermostat. You may find that the actuator motor is not opening the valve. It should move easily with no resistance to the open position. Also I see a fairly new extrol tank. Have you had pressure problems in the past? The red B&G flow check needs to be opened so the tank is not isolated when the zone valves close. The piping is not right, but with the flow check opened manually, it will work. If the wiring is correct, and the thermostat is good, you should have 24 volts to the power head. That will tell you that the motor is no good.

Ibby14

tank

Also I see a fairly new extrol tank. Have you had pressure problems in the past? 



 Do you mean the expansion tank? If that's what you mean then yes. I just had the whole thing overhauled not but a few months ago. It runs better then it ever did (even when new), not to mention that it gets better fuel economy. I inherited this from my mother and I guess it wasn't serviced in years and this house has the worse case of hard water that you've ever seen. The pressure inside didn't blow everything out it actually created a vacuum for some reason, you could see the ribs lining the expansion tank and it created havoc everywhere else, not to mention creating water leaks.



Which would be the cheapest one to replace the thermostat or the valve?

billtwocase

cheapest

the cheapest fix would be to replace only the part that is the culprit. It may be best to call in a tech. It may be better in the long run, and yes I was referring to the expansion tank.

Steve Whitbeck

end switch

The manuall lever will not open the valve far enough to engage the end switch.

You may just need the motor replaced. Not the entire valve head.

Ibby14

switch

OK, here's where my lack of knowledge comes in. I was thinking that that the lever that put the valve on manual was the end switch! So what are we talking about when you talk about the end switch?



Sorry for my ignorance, but I'll know next time!