Reliability of fault codes potterton

[ShaunCorbs]

Apologies, all. It seems that (what I thought) was a TRV on the UFH manifold is, in fact, a "TMV" (Thermostatic Mixing Valve). as oppose to a Thermostatic Radiator Valve (I got a clue when I Googled TRV and saw that the "R" stands for Radiator )

@ShaunCorbs yes, there's a TRV on the radiator that has the grey pipe going to it and I can remove and test anything you would like? Just let me know what you'd like me to do and I'll try it. Thanks

Remove the trv the rad will act like a bypass and the 125 shouldn’t appear

 

[John.g]

Shaun, isn't the existing ABV acting (if in fact its opening at 1.2 M) as a huge by pass all the time with UFH on?.

 

[johnnyt74]

Remove the trv the rad will act like a bypass and the 125 shouldn’t appear

Shaun, isn't the existing ABV acting (if in fact its opening at 1.2 M) as a huge by pass all the time?.

Shaun, really clever solution! Thanks.

I've spoken to the plumber and he has assured me that I already have auto bypass valve fitted and I'm hoping to keep that TRV on that radiator as I spend a lot of time in that room (converted garage) as it has my computer in there and an exercise bike (I'll melt if I can't turn that radiator down!! )

What is the "M" referring to in 1.2M? Is that metres cubed relating to the flow? Could the setting on the ABV be the issue?

Thanks

 

[John.g]

M = Meters, the ABV indexed setting is 0.1 to 0.5Bar which is 1 to 5 meters and as the pump head is always given in Meters (M) I just convert the ABV scale.
Regarding the garage rad, when you have the two systems on (and which subsequently trip) surely you have a number of other rads on? so one (garage) rad with a TRV should have little or no effect IMO.
That setting of 1.2M seems very low.

 

[johnnyt74]

M = Meters, the ABV indexed setting is 0.1 to 0.5Bar which is 1 to 5 meters and as the pump head is always given in Meters (M) I just convert the ABV scale.
Regarding the garage rad, when you have the two systems on (and which subsequently trip) surely you have a number of other rads on? so one (garage) rad with a TRV should have little or no effect IMO.

Thanks for the explanation. Yes, I have rads on through-out the house - albeit at different levels on the TRV's.

Thanks

 

[John.g]

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.

 

[johnnyt74]

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]

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

 

[johnnyt74]

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

Certainly! No harm in trying it. I'll do it over the weekend

 

[John.g]

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.

 

[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