Honeywell zone valves help

[Jonathan]

Not DIY but I would welcome your assistance. My new heating system has two metal covered Honeywell zone valves. when I was testing it at the weekend, steam was coming from a relief valve. The two Honeywell valve levers were in the auto position. Is this correct? Do you expect them to move when the thermostat is tripped?

The heating system is from a back-boiler wood-burining stove and I have had a number of problems with the installers but I wouldn't expect two valves to misfunction in the same way.

Many thanks

Jonathan

[Doctor Drivel]

It depends on how the system is piped up and wired up. What are they trying to achieve.

[Jonathan]

There is a thermostat on the flow and return from the back boiler. When that is tripped the valves should open for the two central heating zones and a pump should pump the hot water round the radiators.

[Adrian]

I'd need to see a diagram - but here's how my woodburner / ch systems was installed at our last house.

The back-boiler had four tapping at the rear - which were piped to two separate heating circuits. One was a 'heat-dump' radiator - gravity-fed and continually operating (as long as there was heat to make the water circulate. The other circuit had a thermostat on the flow which turned on a pump to circulate the water through the dhw cylinder or the remaining rads.

If you were getting the pressure relief valve blowing then this suggests that the zone valves, when shut, are shutting off the flow from the boiler. If this is so then it is potentially very dangerous....

Regards Adrian

[Doctor Drivel]

A pipe stat on the flow pipe. One on the return pipe too? Does it do DHW too? I assume so. So, when water hot enough it is pumped to the cylinder. What about a heat dump if the boiler is too hot? Relying on a pressure relief valve is not good enough.

When the pipe stat is up to temperature then the zone should open as you say. Auto is the correct position for the zones valves. Do you have power to the system? Check the fuse.

[Roger Mills]

That sounds pretty dodgy to me! In order to trip the thermostat, there presumably needs to be a flow of hot water past it. But there won't be any flow until the stat trips and opens the valve and turns on the pump! I think you need to get a detailed description from the installer of exactly how it is *supposed* to work.

[Doctor Drivel]

If the stat is "just above" the boiler on the flow pipe it will work. It needs to be fitted to a vented heat bank thermal store, with unrestricted flow and return pipes the heat bank thermal store buffer cylinder. If too hot the store can switch on the DHW pump with acts as shunt pump and mixes the water in the cylinder (de-stratifying) - this usually works in 90% plus of overheat cases. When too hot a heat dump must be off the store like a towel rail.

If the store is just below boiling point it doesn't matter as the DHW is blended down. The rads will be hot though. If still too hot it just boils over to the F&E tank.

[Doctor Drivel]

There is usually two stages of heat dump. One to a towel rad, the second to the rad circuit.

[Jonathan]

Thank you for your replies.

There are two radiators directly connected to the boiler without valves to allow excess heat to escape.

My question was really to ask if, when the valves are operating correctly, the lever on the valve would be seen to move, as I have expereiced with some other manufacturers.

Thanks

Jonathan

[Doctor Drivel]

Not so. The level stay in the same place. You know when the motor has moved the valve, when you pull the lever and there is no resistance. When it is de-energised and you pull the level you feel the resistance and hear the motor turn.

[dennis]

They don't move on my valves (three manufacturers, one does have an indictor if it was on the side I could see.

[Roger Mills]

The lever doesn't automatically move when the valve opens. But you can tell that the valve *is* open by moving the lever yourself. When the valve is open, the lever will 'flop about' and move to the other end very easily. When the valve is closed, moving the lever opens it - and you can then feel the resistance and hear the gears whirring.

[fred]

In article , Jonathan writes

2 port valves (ie one pipe in & out)?

On Honeywell 2 port normally closed valves the (manual) actuator lever does not move when they are electrically actuated but you can tell if they are actuated as when attempting to move the lever in this state you will experience little or no resistance to movement.

If you find they are closed you could manually open them to see if that makes a difference to the system operation.

In a gas system where power failure would take out the boiler too I would expect to see normally closed spring return valves eg Honeywell V4043H.

In a solid fuel system like yours I would expect to some kind of flow path maintained in a power failure, perhaps by use of normally open valves such as Honeywell V4043B, so as to ensure a fail-safe system.

[Roger Mills]

[Roger Mills]

[Sorry about the empty message - finger trouble!]

Chances are that the valves are perfectly ok. What is more in question is the system *design* - and perhaps whether the installers have used the correct type of valve for this particular application.

[Doctor Drivel]

That depends on how it has been piped up. If the F&Es vent and feed pipes are direct to the boiler then no problem with using normally closed zone valves.

[Doctor Drivel]

Steam coming from a relief valve tell me it is not pipe up right and/or a Honeywell V4043B normally open valve should be used on DHW