Very hot radiators very quickly following HW being on.

[sorethumb1]

Hi all. Hoping for some advice.

I have s plan configuration heating system (oil) consisting of three 2 port motorised valves. Two of these are of type danfoss hpa2 for each of the CH zones, the other a tower for HW.

I have two room stats one for each zone, but I don't have a programmer/clock which can control each zone individually (if you get my meaning) so relay on stats clicking heat on/off in each zone.

Problems started about two months ago, following return from a fortnight holiday. Where neither heating or hot water was on

Firstly, the solenoid coil went at burner and was replaced, oil pump then went and was replaced then one of the danfoss actuator which controlled the valve body for one of the central heating zones stopped working and it was replaced also.
Now my heating system works fine for most part however some times, when I would select HW only and leave it on for say 30 minutes when I then switch off HW at the clock or cylinder hot water stat switches it off and I then were to switch on CH only for say 30 seconds, all my radiators in one of my heating zones will get very warm very quickly, almost like all the warm water from HW curcuit is getting into CH butthis only happens intermittently.

I'm by no means an expert in any of this and have done my best to try and research to this point it's just now I'm getting all sorts of different opinions from as to how to fix problem. Some are saying it's a microswitch on head of one of the CH zone actuators at fault, some saying valve body and head of HW needs replaced as bypassing, some even said it's wiring problem get an electrician. This has never been a problem before. and the only thing that had changed is that new actuator was wired in to replace one that had been failing to energise.

Really hope someone could shed some light on the problem.

Many thanks in advance.

 

[sorethumb1]

Anyone??

 

[kidgreen61]

You haven't said what type/model boiler you have, but,
either you have a zone valve passing, which you can check out by process of elimination, ie the outlet pipe (from any valve) shouldn't get hot when that valve is not in use.

Or, the boiler may have pump overrun facility, and the by-pass may dump the heat (incorrectly) in a rad circuit.

 

[D_Hailsham]

when I would select HW only and leave it on for say 30 minutes when I then switch off HW at the clock or cylinder hot water stat switches it off and I then were to switch on CH only for say 30 seconds, all my radiators in one of my heating zones will get very warm very quickly, almost like all the warm water from HW curcuit is getting into CH but this only happens intermittently.

the only thing that had changed is that new actuator was wired in to replace one that had been failing to energise.

Does the boiler light during this 30 seconds?

Each valve cable has four wires - Brown, Blue, Grey and Orange. Brown and Blue control valve opening; Grey and Orange connect to the microwitch which turns the boiler on.

Check that all three Orange wires connect to the same terminal, and all three Grey wires also connect to the same (but different) terminal. If there are two of one colour and one of the other, swap the single colours over.

Check the valves are not sticking by moving the lever from Auto to Man. You should feel resistance as you move the lever. It should automatically return toe Auto when released. If there is no resistance (lever feels loose) the valve is stuck open.