Vaillant boiler issues F28 on ecotec 430 not the normal culprit

[ShaunCorbs]

i would get a llh fitted and the added items to get the system working right then if all else fails this can be still used for a new boiler etc

you sure the new gas main is 63mm seems big

 

[Navi Bhander]

i would get a llh fitted and the added items to get the system working right then if all else fails this can be still used for a new boiler etc

you sure the new gas main is 63mm seems big

63 mm to just under the meter where it reduces to whatever goes into the meter.

 

[Navi Bhander]

Also just a thought here, with my limited knowledge.

If we separated the 2 boilers, one for the underfloor heating so the temperature could be set lower and the other one doing hot water and radiators. As the boilers have CH and HW function on then I wouldn’t really need the LLH? I would just need another boiler wiring centre, and 2 pumps, one for Hw and CH.

 

[ShaunCorbs]

The underfloor heating one wouldn’t like it tbh would cycle like a mother when one or two zones are open

TBH I would keep it as is and sort the pipeing out etc

 

[Navi Bhander]

The underfloor heating one wouldn’t like it tbh would cycle like a mother when one or two zones are open

TBH I would keep it as is and sort the pipeing out etc

At The moment I get 2 boilers firing up for it!

The issue Andrew has by leaving the boilers paired is the hot water cylinder will take longer to heat up as the boilers will only be running at 65’c. Increasing it will make them condense or something or another. I’m an osteopath so a fair bit goes straight over my head!

 

[ShaunCorbs]

I think he means when he separates the boilers as you won’t have 60 kw going to the cylinder only 30kw

Potential with no other load etc

Cylinder will be happy with a flow of 65

 

[Navi Bhander]

Just an update.

With one boiler switched off the other boiler still triggered a F28 code yesterday.

Interestingly I have noted one thing.

It seems to trigger the F28 on the central heating demand for the radiators. As it was a very mild day yesterday the only zone active in the house was our bedroom as it’s set to 20’c as there is a new born in the house.

The evohome system switches the boiler on for 1 min every 10 mins or so to regulate the temp. In reality what happens is the bdr91 relay switches on, the pump switches on but by the time the boiler ignites it only runs for a few seconds before it switches back off as the relay switches off.

Could this scenario some how cause the boiler has supply issue as it’s just ignites and then switches off due to the demand not being required anymore?

I’m mechanically competent and used to restore classic cars. If you start a car but switch it off without it fully turning over it sometimes results in it flooding and difficult to start the next time. In very layman terms could this happen with gas?

 

[ShaunCorbs]

It’s a possibility I would turn that off and make it run for a min of 5 mins before it switches off

 

[Alex Price]

Hi, has anyone tried disconnecting all outside controll interface to the boilers, put the jump cable back in to call for heat and run each one Independently?

I have known a split controll interface spike between the two sides, if the draw on the switch is great enough it can cause some weird resistance values and that can cascade through the pcb, Biasi and morco air pressure switches are good for that. gas supply sounds iffy for the pair but the only constant seems to be the call for heat, Worth a try ?

 

[ShaunCorbs]

Hi, has anyone tried disconnecting all outside controll interface to the boilers, put the jump cable back in to call for heat and run each one Independently?

I have known a split controll interface spike between the two sides, if the draw on the switch is great enough it can cause some weird resistance values and that can cascade through the pcb, Biasi and morco air pressure switches are good for that. gas supply sounds iffy for the pair but the only constant seems to be the call for heat, Worth a try ?

Yep simple controls

 

[Antonio Dinis]

Hi there
See if this helps

 

[Antonio Dinis]

By the way I’m a gas engineer

 

[Antonio Dinis]

Pure or plus are the same on this case

 

[gmartine]

It seems to trigger the F28 on the central heating demand for the radiators. As it was a very mild day yesterday the only zone active in the house was our bedroom as it’s set to 20’c as there is a new born in the house.

As tempting as it is (because you can) trim down demand to the odd radiator. Unless you have a boiler that can modulate 20:1 or so your boiler is not going to like it one bit so open up a few zones/rads even though it seems counter intuitive.

 

[Riley]

By the way I’m a gas engineer

Then please pm your details to @Riley @ShaunCorbs or @Harvest Fields and we can arrange for you to gain your gsr tag and access to gas safe only area. Until you have it then please be wary on commenting on gas issues as our members need to know that we talk gas safety very seriously. Keep posting, introduce yourself hang around. Very nice to have you

 

[Abuali]

Not withstanding the F28, it would appear you have a you have 2 oversized boilers on a poorly designed system, I take it from the single large pump that there is no low loss header installed? (60kW through 28mm what were they thinking !!!)

Why haven't you gone back to the installer / manufacturer before now?

When you go down to reset, is it both that show the F28 ??

I agree with you on the Low Loss header installation but regarding the single large pump and the 28 mm pipes what could they have done if the pipe installation was there and it was not possible to amend the pipe work as for example its all within the house without them being able to rip the flooring up and and install smaller pumps for each area/floor.
What would you have done differently?
Thanks in advance

 

[Riley]

I agree with you on the Low Loss header installation but regarding the single large pump and the 28 mm pipes what could they have done if the pipe installation was there and it was not possible to amend the pipe work as for example its all within the house without them being able to rip the flooring up and and install smaller pumps for each area/floor.
What would you have done differently?
Thanks in advance

There’s pretty much always ways. It just needs careful planning and design

 

[Abuali]

There’s pretty much always ways. It just needs careful planning and design

Would very much appreciate your ideas.
I will be very thankful if you can elaborate more on that.

 

[Riley]

Depends on space, where pipes become accessible, is there a basement, can zones be set up differently. Too many variables to give a one size fits all response

 

[Abuali]

Depends on space, where pipes become accessible, is there a basement, can zones be set up differently. Too many variables to give a one size fits all response

I agree its hard to generalise.
But if you are colled to change a two old boilers installed in series to new boilers and all what you see is that the old boilers installed without low loss header.
The new pipe work installation includes you installing a UF heating in the basement floor and with the client dont want to re-pipe the pipe work installation.
Now you left with a boiler room and only u can see two old boilers with two zones valves that you cannot be sure wt areas they control, the pipe work from the boilers room under the street to the house is 35mm run then to 22mm all over the house. (No plans for the old pipework run, most floors are marble tiles!)
A house with 5 floors(incl lower ground flr where the underfloor heating installed on three circuits) each floor area is around 120 sq m with around 25 radiators allover the house and 210l HW cylinder.
What options would you do apart from installting a low loss header and a single large pump .
Any ideas would be highly appreciated