It was on the earlier locked thread, entitled something like "15mm or 22mm".Compare with what figures ?
It was on the earlier locked thread, entitled something like "15mm or 22mm".
Taken that as 50kW output, so input at ~ 96% eff, 52kW, gas flow 4.64m3/hr. Not sure what you mean by high loss fittings, so I assumed 90° elbows.Ok- 50kw, 12 meters, 14 high loss fittings.
What pipe size and loss do you get ?
Taken that as 50kW output, so input at ~ 96% eff, 52kW, gas flow 4.64m3/hr. Not sure what you mean by high loss fittings, so I assumed 90° elbows.
As the pressure loss most likely needs to be in the region of 1mb, I did 2 pipe sizes.
Nominal 22mm, 2.14mb
Nominal 28mm, 0.73mb
What do you get? I've shown you mine....
What's the matter with you? I thought we were having a sensible discussion.As we all know it’s 1mbr max loss. So 22mm won’t do! That’s not an ambiguous figure. It’s the basic requirement.
50kw needs to be 28mm minimum. That would give a loss of 0.760mbr
So there you go........
Edit: And as above max length @19m in 28mm
I think that proves you give gas advise without the proper knowledge?
That's right, I mentioned it and showed it was too small. Shall we leave it at that?The problem is you mention 22mm pipe with an unacceptable loss. Your 28mm is ok.
1mbr or less is ok.
That's right, I mentioned it and showed it was too small. Shall we leave it at that?
What's the matter with you? I thought we were having a sensible discussion.
I had just that problem - 240volt to the gas valve (SIT as here) but it wasn't firing. Turned out one of the solenoids (of 2) was open circuit. I got one from Solenoids UK for £12 which worked OK, but the connector was in the wrong place so needed a temporary wiring fix. The replacement from Italy was £37 after various outfits had taken a cut.if it is the pcb and i am not saying that it is, nothing to stop you changing it yourself on that boiler, when your system fails check to see if you are getting 240v to the gas valve , if you are and the boiler isnt on, then im sure as an electrician you can work out what the fault is, if you arent then work your way back
Agree they normally fail to OC but have seen the valves sticking intermittently, not common but can happenI had just that problem - 240volt to the gas valve (SIT as here) but it wasn't firing. Turned out one of the solenoids (of 2) was open circuit. I got one from Solenoids UK for £12 which worked OK, but the connector was in the wrong place so needed a temporary wiring fix. The replacement from Italy was £37 after various outfits had taken a cut.
But the fault was not intermittent like the OP's problem.
What I'm trying to find out is what I (as a maintenance electrician) can do before I have to call out a heating engineer, for instance can I rule out the 3 port valve? Or is the consensus that it's either the PCB or one of the gas valves? If it's the gas valves I'm taking it that it's more likely to be the valve mechanism that's sticking rather than the solenoid actuator not energising, If it's the PCB (and this was changed in the last 4 years) is that possible to change without going near the gas side of things (which I wouldn't).
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