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Discuss Reliability of fault codes potterton in the Central Heating Forum area at PlumbersForums.net

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24
Something strange alright as ironically, the more the rad TRVs throttle in the more the set up tends to the UFH side (no trip). Is the ABV very hot on both sides of the pipework.
I think monitoring the boiler flow temperature later on will tell a lot, hopefully.

Also if the rad system is on alone then you can get huge deltaTs with no by pass and TRVs, my oil fired boiler regularly has a delta T of > 35C as I have no by pass fitted so again strange why your system doesn't trip on the rad system only.
The full fault description of E125 is:
Circulation Fault (Primary Circuit)

Displayed in either of two situations:
- If within 15 seconds of the burner lighting the boiler temperature has not changed by 1°.
-If within 10 minutes of the burner lighting the boiler temperature twice exceeds the selected temperature by 30°. In these instances poor primary circulation is indicated.

So, are you saying that the DeltaT is the measurement for that second fault reason (If within 10 minutes of the burner lighting the boiler temperature twice exceeds the selected temperature by 30°. In these instances poor primary circulation is indicated.) ?
 

ShaunCorbs

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Can we just try removing the trv head for a day or two when you want either on will prove if there’s no flow eg no auto bypass on the primary’s
 
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2,010
The full fault description of E125 is:
Circulation Fault (Primary Circuit)

Displayed in either of two situations:
- If within 15 seconds of the burner lighting the boiler temperature has not changed by 1°.
-If within 10 minutes of the burner lighting the boiler temperature twice exceeds the selected temperature by 30°. In these instances poor primary circulation is indicated.

So, are you saying that the DeltaT is the measurement for that second fault reason (If within 10 minutes of the burner lighting the boiler temperature twice exceeds the selected temperature by 30°. In these instances poor primary circulation is indicated.) ?
If it's the deltaT that its monitoring then yes, definitely a indication of poor circulation, but the actual wording doesn't say that, its says:
"the boiler temperature twice exceeds the selected temperature by 30°. In these instances poor primary circulation is indicated" which I interpret to mean that the boiler temperature must exceed the target or set point flow temperature by 30C, so if you have the boiler target (setpoint) temp set to 65C then the boiler flow temperature must exceed 95C before flagging this alarm/trip and perhaps this what is happening.
 
Messages
24
If it's the deltaT that its monitoring then yes, definitely a indication of poor circulation, but the actual wording doesn't say that, its says:
"the boiler temperature twice exceeds the selected temperature by 30°. In these instances poor primary circulation is indicated" which I interpret to mean that the boiler temperature must exceed the target or set point flow temperature by 30C, so if you have the boiler target (setpoint) temp set to 65C then the boiler flow temperature must exceed 95C before flagging this alarm/trip and perhaps this what is happening.
I wonder if you've maybe just hit the sharp pointy thing on the end with that statement.? I have noticed the boiler temperature climbing up to 80+ and then slowly coming back down again... It seems to climb when the UFH is calling for water/heat. I wonder if the flow at the UFH is on the feathery-edge of tripping the boiler based on this?

Previously as well, the boiler radiator temperature was turned right down (I've since turned it up to 65 deg previously it was only at around 40 deg) which would obviously lower the tripping out temperature....??

Hmmmm... I'll keep an eye on the temperature when I have a play around with it later.

Thanks :)
 
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2,010
The burner should cut out at the setpoint+5C if the heat demand is less than the boiler minimum outpout and the circ pump should run on (pump overrun & anti cycle time) for a fixed time maybe 3 minutes or so and if the Rads or/and the UFH are still calling for some heat then they will/should reduce the return and flow temperatures by say 10C, the burner will then fire up and continue to fire until the above happens again OR until no demand for heat from both the UFH & Rads in which case there must/should be a bypass either automatic or a rad (without a TRV) to allow circulation and cool down the water as the zone valves will have closed. So don't know if the ABV shown is on the primary flow and if its orientated properly or if its full of sludge with no effective by pass as a setting of 1.2M should by pass more than enough IMO, they might normally be set to 0.30/0.4 Bar (3M/4M). to prevent too much by pass and starve the UFH or whatever of hot water.
 
Messages
24
The burner should cut out at the setpoint+5C if the heat demand is less than the boiler minimum outpout and the circ pump should run on (pump overrun & anti cycle time) for a fixed time maybe 3 minutes or so and if the Rads or/and the UFH are still calling for some heat then they will/should reduce the return and flow temperatures by say 10C, the burner will then fire up and continue to fire until the above happens again OR until no demand for heat from both the UFH & Rads in which case there must/should be a bypass either automatic or a rad (without a TRV) to allow circulation and cool down the water as the zone valves will have closed. So don't know if the ABV shown is on the primary flow and if its orientated properly or if its full of sludge with no effective by pass as a setting of 1.2M should by pass more than enough IMO, they might normally be set to 0.30/0.4 Bar (3M/4M). to prevent too much by pass and starve the UFH or whatever of hot water.
I wonder if the UFH heat could be 'patchy' because not enough water is getting to it? It's all being bypassed?

I'll mention it to the plumber tomorrow when I see him. Thanks :)
 
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2,010
Hope your plumber has arrived. If you look at the attachment sometime can you confirm my queries (text), also presume the rads are plumbed in further back on the same piping but with zoning?.
 

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Hope your plumber has arrived. If you look at the attachment sometime can you confirm my queries (text), also presume the rads are plumbed in further back on the same piping but with zoning?.
Yes, the plumber turned up first thing thanks. He said that the jobs not finished and he's going to get it sorted. He's thinking that it's all to do with air in the system and that he'll get it sorted. Although he left and I've not seen him since so not sure if he's sorting it today or coming back next week?

To answer your questions in the text on the image - yes, those pipes were run just for the UFH and arrive (without interruption) back into the "boiler cupboard" as marked on this image. I'm not sure about your "presume the rads are plumbed in further back on the same piping but with zoning" question as I can't make head or tail out of the pipework in the boiler cupboard? So, can't really say? I presume so.
 

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While you are waiting maybe try ShaunCorbs suggestion first and if no joy increase the ABV setting to say 0.25/0.3bar and note the UFH flow gauge readings before/after any changes, you can always change it back after your tests.
 

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