help with ecoTEC valliant 831 and heating

[MW9]

This is the air vent to vent the pump and boiler after refilling as without venting the boiler the radiators weren’t getting hot even after couple hours, not even the closest one fully open

This could be an issue why they weren’t getting hot after x400 being in the system for months, after I drain it, I get that I didn’t drain it many times but this could have been one of an issue as well

 

[Johntheo5]

You might think that this problem would alo show up in DHW mode, but in your case since only one HW tap is serviced by the combi probably wasn't apparent as this tap probably only flows ~ 6/8LPM ?

P.0 Bleeding test program. The heating circuit and hot
water circuit (combination boiler only) is bled via the
automatic air vent (the cap on the automatic air vent
must be loosened).
3.11.3 Venting
The boiler is fitted with an automatic air vent. Additional
provision should be made to enable the heating system
to be vented during filling and commissioning either by
automatic air vents or manually.

 

[MW9]

They should have made this vent more accessible for normal user to use after draining/refilling so you don’t need to take the cover off. Or made it automatic that if you go to that program on the boiler it opens automatically. I will report back when I’m back on Saturday and drain the x800 few times and refill with clean water. Fingers crossed.

I will test it with clean water first before adding inhibitor.

 

[Johntheo5]

Very good, one more query (just now), how does the return temperature (by hand) compare with d41?.

 

[MW9]

Much warmer than it used to be more like when I was just running cylinder, I can still hold it without being burnt but it is very warm, so I recon it’s still lower than what d41 shows 68/70. Once I’m back I will take the cover off and compare with return pipe inside the boiler and I will connect the thermometer to both of the return inside and outside boiler.

 

[MW9]

So I have drain the system multiple times after putting the x800 on Thursday, I have run the water as well through the radiators with air vents closed and drains open and filling loop open so a lot of water went through the radiators and I was closing certain drain to change the direction of water. (Some darker water came out on the beginning and some small black bits but nothing drastic)

I have adjusted the lock shields and run heating without the TRV heads on radiators, and the radiators are getting hot/very warm even the problematic one gets hot, the boiler is not overheating/ cutting off when it gets to 75 usually it stay at 75 it does not cycle like it used to before even when I put pump on auto now.

So I have decided to put the trv heads on and the radiators are playing up again even with the trv on max, as soon as I remove trv the hot water comes in to the radiator,

It looks like they are no branded ones as Drayton would have a name on them and the valve looks like the none adjustable ones so the trv heads must be playing up.

It’s probably combination of few things but now I can get the radiators hot without the heads and boiler is not overheating (I’m not checking the return temp as it’s probably the same 5degree difference we will check the flow filter tomorrow),

I will look for some other TRV heads brand on Amazon prime and test them if they work I will replace those rubbish ones.

Unless those non branded trv cutting out as it’s 25 in the room? But in max they should be working to around 30?

 

[Johntheo5]

I use and have used a variety of basic TRVs for years, they last ~ 6 to 8 years although 2 are around 18 years old, working fine. I am using EPH EMPTRV15 for the past 6 years or so and find them excellent and won't break the bank, they come with a L/S valve as well but can probably be bought without these.
I would suggest renewing the whole TRV and not just the actuator as there can be slight differences in the actuators which may give problems as the pin only moves ~ 5mm, or maybe, as you say, to test, just buy one/two actuators of your choice (use a well known brand) and try them on one/two of the existing valves.

The EPH ones have index setting of 0=0C. *=7C. 1=12C. 2=16C. 3=20C. 4=24C. 5=28C.

 

[MW9]

It’s a shame as they were installed as brand new when we moved in 2019 but I didn’t know they are not Drayton as they look the same as our old house so thought it’s the same brand.

Would be good if the different heads just work as I’m not fancy changing all the valves again in all radiators.

I might just wait for winter as well to see how they work I remember having issues in winter as well but this was with the boiler cutting off now with it working much better it could be different story. And the problematic radiator which was cold had the trv head removed already and it was still cold, so definitely something has improved after those cleaning chemicals.

 

[Johntheo5]

Wht's inside in the container?, apart from water.

 

[MW9]

You mean the plastic box in the pic above?

X800, water, and few black bits which I think have dissolved and started floating after x800 was out in. It was from the first drain, the next drains was clear.

 

[Johntheo5]

Yes, it looks like a clear plastic film, broken in the middle.

 

[MW9]

It might be the hose under I have put some zoom and how water looked after few drains.

 

[DP]

You mean the plastic box in the pic above?

X800, water, and few black bits which I think have dissolved and started floating after x800 was out in. It was from the first drain, the next drains was clear.

X800 needs removing properly. If not done correctly, pump/s will need replaced regularly

 

[MW9]

An update:

The filter removed, it was proper stuck didn’t want to barge, we needed to insert inspection camera to actually see if it’s there after removing I rinse it in the glass to see how dirty it was and to be honest it’s quite a bit of dirt for such a small part

The other issue is the screw on the bypass is stuck as well it won’t move with no matter how much force you use to the point that the head snapped from the screw, and if you remove the plastic part from diverter so it’s full on heating the radiators get hot very quickly and I have seen 12 degree difference on the d41.

So we will get that part and replace on the next visit but looks like we are getting there. In therms of the TRV heads I think they might be working but they have much lower cut off then Drayton perhaps 22-25 rather then 30 on Drayton which was messing with my and my balancing, I have put the aircons today and when the temp in the room drops to 18 the radiators open up and slowly heat.

So I think after resolving that flow issue and bypass I think I might be good in winter now. Fingers crossed

 

[MW9]

This is now when it’s heating up I have 13 degree difference between flow and return which I have never seen before it was always 5. And the boiler it’s not cycling as it used too.

I’m still using the old diverter valve with stuck screw as this will be replaced on next visit but it’s working much better so far.