ian
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Posts: 294
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Post by ian on Nov 14, 2019 21:05:01 GMT
Some rads are getting hot (mainly upstairs but some downstairs are getting hot too) others aren't. The main culprit is a 1800 double panel in the living room. Its on 10mm pipe and furthest from the boiler. Balancing does no good and closing the other rads doesnt even make it come fully hot.
Pipes are clear, system is clean, valves are new (problem existed before new valves).
The boiler fires up and the temperature climbs far too fast and burner turns off before rads get hot, after a few cycles some rads get hot and then no more improvement.
Inspected pump, working fine, impellor clean and not broken or loose on the shaft.
Felt around the secondary heat exchanger and it is geting hot when just the heating is on. It would appear the divertor is stuck part open and short circuitung the flow.
Before a new divertor is ordered i was wondering if anyone has anything to add?
Which usually fail? Motorised head or the cartridge?
System has been drained down to change 3 rads to doubles but the problem existed before hand and the boiler (10years old) heats all the rads well when working. ( albeit before the change to doubles, the cold 1800 was one that was changed but was cold before too.)
Pump isnt air locked and aav is working properly. All rads been bled and balanced.
Have i missed anything?
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Post by tomplum on Nov 14, 2019 21:57:28 GMT
I'd say its not piped properly, maybe took from another 10mm branch, just guessing ,
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ian
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Posts: 294
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Post by ian on Nov 14, 2019 22:11:05 GMT
Thanks for moving this to the right section.
The rad has worked properly before so i think the piping is ok.
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Post by tomplum on Nov 15, 2019 8:56:07 GMT
So if it worked ok before it can olny be semi blocked or air locked and as you have shut every thing down except that rad, Its gotta be a blockage, check the valves first, if they are ok do the foot pump trick the foot pump trick |
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ian
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Posts: 294
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Post by ian on Nov 15, 2019 10:38:49 GMT
Its got new valves and the pipes are clear. Have blown down both sides and cut out a crook from each side thinking it could be trapping crud. All clear and system was really clean. Even when i tipped the old rad on end not much black came out.
put some x800 cleaner in for the sake of it a couple of days ago and the water is still only slightly dirty.
Im leaming towards the divertor being knackered/jammed and shortcircuiting the heating flow as the secondary heat exchanger is getting red hot when there is only demand for heating.
The boiler also gets up to temp very faat and the burner stops before any rads get hot.
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Post by tomplum on Nov 15, 2019 12:27:55 GMT
That shows its not circulating, is the pump running ok ?
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ian
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Posts: 294
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Post by ian on Nov 15, 2019 13:15:45 GMT
That shows its not circulating, is the pump running ok ? Pump runs fine. took it off last night to checked the impellor and its clean and solid on the spindle. |
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Post by tomplum on Nov 15, 2019 13:29:55 GMT
so then its the motorized valve or blockage but, never rule out an airlock, they can send you off track, they where invented by the devil himself,  |
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ian
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Posts: 294
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Post by ian on Nov 15, 2019 14:25:38 GMT
so then its the motorized valve or blockage but, never rule out an airlock, they can send you off track, they where invented by the devil himself, I checked the aav was working and bled the pump. The run of the pipes seems reasonable (up to the ceiling, along the landing under the floor and up again into the boiler cupboard.) Seems easy enough to whip off the divertor so worth a quick look. Can get a head and cartridge for £10 each and they have told me occasionally the water has run cold when drawing a bath and occasionally the cold rad would get hot. Also have to drain the system to replace the cleaner with inhibitor so will whip the valves off and blast both sides through with the filling loop to be sure there is no air and good flow. |
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Post by battle1066 on Nov 15, 2019 17:12:27 GMT
So you inherited his job with the faults on cause the early overheat cutting off would worry me.
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ian
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Posts: 294
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Post by ian on Nov 15, 2019 17:57:21 GMT
So you inherited his job with the faults on cause the early overheat cutting off would worry me. Pretty much. It doesnt worry me, i like a challenge. |
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Post by crowsfoot on Nov 15, 2019 18:21:15 GMT
So you inherited his job with the faults on cause the early overheat cutting off would worry me. It could indeed be a faulty low limit stat on the boiler itself, if the boiler temp climbs rapidly past the low limit stat level then shuts off on the high limit stat and then refuses to come back on until it all goes cold? Interesting problem this one Ian. It's been over 12 years since I last worked on gas boiler's so I'm not up to scratch these days. Hope the boiler doc spots this posting his input on it would be good. Tappy, |
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Post by battle1066 on Nov 15, 2019 18:26:56 GMT
So you inherited his job with the faults on cause the early overheat cutting off would worry me. Pretty much. It doesnt worry me, i like a challenge. It's the twiddlers before you that make the actual job difficult. |
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Post by dickpuller on Nov 15, 2019 20:44:34 GMT
Hmmm..... not an old boiler!! Are the valves below the boiler ON, take the plastic handles off & check the VALVE orientation.
Is there a filter on one of the valves, is it clean?
All boiler thermistors need to be checked too. Thermistors are shite on Baxi/Potty boilers.
After all that you need to check the Diverter valve as said by my Learned Friend.
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Post by glowbug on Nov 16, 2019 1:41:59 GMT
To check motorised head ,release clip, and hold plastic head in hand , looking at gibbons, when heating demand is put on ,pin should move forwards and be solid,🧐that’s the quick way , or if you want get multi meter out ,good luck in your mission👍
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