Reliability of fault codes potterton

[johnnyt74]

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

 

[John.g]

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.

 

[johnnyt74]

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

 

[John.g]

Yes, that's a real possibility, I think you have flow meters which should indicate the flow through each UFH loop in LPM.?

 

[johnnyt74]

Yes, that's a real possibility, I think you have flow meters which should indicate the flow through each UFH loop in LPM.?

Yep, I think the system definitely needs balancing anyway. Thanks again. Your help has been superb

 

[John.g]

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?.

 

[johnnyt74]

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.

 

[John.g]

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.

 

[johnnyt74]

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.

Yep, good idea. I'll hopefully get to do that over the weekend. I'm currently boarding out the extension so like to keep the floor off during the day (as it sweltering otherwise) but I want to test a few things this weekend and try and get to the bottom of it.
Thanks for your help. I'll post back with any developments

 

[johnnyt74]

Just a quick update on this.... I've not had another trip since the plumbers visit. He bled all the rads when he came and he phoned Saturday and told me that he's 100% convinced it's just air in the system and that it just needs time to settle and bleed off.

He's going to test it next time he's here and, if necessary, "blast the air out of it". But he's hopeful the air will just dissipate as it's used. I put the heating and UFH on simultaneously every evening since Thursday and (fingers firmly crossed) the E125 fault hasn't returned?

So, I'm hoping he's right. Assuming the UFH was full of air, I was wondering if that would restrict the flow of water, therefore making the boiler temp go over the "30 deg above set point" rule and therefore faulting on E125. It makes sense in my tiny, non-plumbing brain??