28cdi combi with f and e

[armyash]

Hi guys,

been out to this boiler, it's a combi but it's not a sealed system it's tank fed.

never seen this before.

customer has complained that hw is intermittent. Colleague of mine has said change the plate. I'm not entirely convinced, went through fault finding, checking pressures and resistances etc and it was pointing to pcb.

Hw hw either boiling hot or hot and cold.

Possibly a sensor?

what do you think? Ever seen this set up before?
thanks

 

[ShaunCorbs]

is there a pressure gauge? and same never heard of one being set up like that

 

[kris]

I have heard but never seen this. Its someone trying to re use the f n e tank when new boiler fitted ... it should be pressurized as the f n e tank is simply for filling the heating.... stupid really

 

[ShaunCorbs]

I have heard but never seen this. Its someone trying to re use the f n e tank when new boiler fitted ... it should be pressurized as the f n e tank is simply for filling the heating.... stupid really

you wouldn't get enough pressure by just the tank you would need a pump/ pressure tester to force it in?

 

[Linkyplumb]

have seen it, and done it on very old systems, whereby you fit a plate heat exchanger in the system, thus having the heating circuit (from combi) through the plate pressurised, and open vented on the other side of the plate.

If it has been done this way then pressure should be filled and read at the boiler, ie on boiler filling loop and gauge

 

[Nostrum]

It was an approved method on the CDI and was in the MI believe it or not!

Have you checked the min and max burner pressure?

 

[Nostrum]

 

[hammers4spanner]

Halstead set up around my way like that , plus vokera can work like that.

 

[Ray Stafford]

Blimey, you youngsters!

I remember selling Worcester heatlaves with an F&E tank on top of the boiler!

<plays hovis music>

 

[ShaunCorbs]

Blimey, you youngsters!

I remember selling Worcester heatlaves with an F&E tank on top of the boiler!

<plays hovis music>

[video=youtube_share;6Mq59ykPnAE]https://youtu.be/6Mq59ykPnAE?t=13[/video]

 

[stevetheplumber]

wasnt that uncommon ive seen quite a few why would it not fill kris and sean ? its just an open vent system you boys are so used to pressurise fill

 

[ShaunCorbs]

wasnt that uncommon ive seen quite a few why would it not fill kris and sean ? its just an open vent system you boys are so used to pressurise fill

would the boiler have a min pressure like todays of .7-.8 as its a combi ?

 

[Leo21]

You need to be in for you the boiler, and see how hot it's getting. Is it firing and cutting in and out? Which means circulation or shut down via electronics. Find out the spresiatances for the sensors, or just do it by feel and temps.

 

[lame plumber]

You need to be in for you the boiler, and see how hot it's getting. Is it firing and cutting in and out? Which means circulation or shut down via electronics. Find out the spresiatances for the sensors, or just do it by feel and temps.

been on the booze leo, you dont seem to be able to get the words out very eloquantly

 

[Leo21]

It's funny you should day that......

 

[stevetheplumber]

ive got an eco tec thats running from a tank supply done by accident as we took the cold feed of the supply to the electric shower wasnt til 4 years later when i had to do something else in the flat we found out it was from a tank 4 floors higher

 

[buckley plumb]

It was an approved method on the CDI and was in the MI believe it or not!

Have you checked the min and max burner pressure?

I agree in the manual

 

[buckley plumb]

Didn't the aps used to be a problem on those would work on Heating but drop out on hw

 

[armyash]

Burner pressure and resistances checked.
Will go for the plate before anything else

 

[Nostrum]

Burner pressure and resistances checked.
Will go for the plate before anything else

I've replaced a PCB on these for the same issue. The boiler wasn't controlling the gas valve modulation correctly.

 

[newcastle phill]

I serviced one on that set up a while ago. Customer hadnt long been in.
Concealed pipework and I tried to top up until the guage didnt move lol. Poked head in loft and saw it was tank fed.
This example was a poor performing system as was also piped in microbore ! And a complaint was far rads on drop downs not getting hot.
This setup is in MI - as above

 

[buckley plumb]

I've replaced a PCB on these for the same issue. The boiler wasn't controlling the gas valve modulation correctly.

You have just refreshed my memory. I remember changing pcb once as boiler kept going off. If it is pcb worcester do fixed price repair would be cheaper for customer as pcb was over £200 from memory. I am finding around here unless I diagnose correct customers won't pay so unless sure now I advise manufacturer fixed price Repair.

 

[armyash]

You have just refreshed my memory. I remember changing pcb once as boiler kept going off. If it is pcb worcester do fixed price repair would be cheaper for customer as pcb was over £200 from memory. I am finding around here unless I diagnose correct customers won't pay so unless sure now I advise manufacturer fixed price Repair.

This is why I think it was the pcb, the burner pressure was steady down at 1.5mb on hw but didn't ramp up when was supposed to.

Changed plate today, hw was running ok and boiler was staying on but hw seemed to be coming very hot!

Cust said seemed better - probably just happy it was staying on but if I have to go back will throw the pcb in.