Remeha avanta plus 28c problems

[Hobo128]

Hi

Been out to said boiler today with a lack of dhw temperature. Turn the hot tap on a water is only luke warm. Checked the thermistors which seem fine and have taken the plate hex off and given it a clean out. Still no joy. Im thinking it could be the diverter cartridge but as they are costly and haven't worked on these boilers before wanted some advise first.
Any input would be appreciated.

Cheers

 

[bewsh]

When you run the hot tap, does the c/h flow pipe get hot? If so, diverter is passing.

Also, have you checked the flow rates/temperature rises against MI's?

 

[GrahamM]

Good tip from Bewsh.
You say you cleaned the Plate....how did you clean it? Let it sit in some spirit of salts or something for few hours?

 

[Hobo128]

When you run the hot tap, does the c/h flow pipe get hot? If so, diverter is passing.

Also, have you checked the flow rates/temperature rises against MI's?

Hi mate, I haven't checked the flow rate or temp rise with mi as it seemed to be working fine before. The c/h flow pipe does get hot but right up close to the boiler. It doesn't all get hot.
Could this be the cause, it seems to be giving all types of strange symptoms heating shutting of prematurely,luke warm hot water, running hot water then turning heating on takes ages to get warm, that type of thing. What do you think? Also, the plate hex didn't seem bad really. Just put a bit of sentinel in for a short while. But song think that was the problem.

 

[gassafe]

It's difficult to tell how clean the plate hex is by looking in the holes!, and having a bit of sentinel in it for a short whole probs did nothing!!

 

[GrahamM]

I have seen a cross section of a bunged up Plate and as gassafe mentioned some sentinel in it for a short while will have little or no effect.

You now mention there is other issues as well as hot water. Have you had look at how dirty the heating system may be and checked the usual suspects.....pump function, airlocks etc.

 

[Hobo128]

Yes, checked pump. Done resistance test, checked it's running. Checked for any airlocks, system is abit dirty though as I have had a rad of and flushed out a bit a dark water, plate hex was abit black. I can see a sludge build up maybe causing the problem as in seizing up the diverter valve etc but not sure.

 

[AlexGas]

... Just put a bit of sentinel in for a short while.

If you do that, you'll be better off using FX2 from Kamco, that's acid.

 

[bewsh]

If you suspect the plate heat exchanger is blocked, you could check the temperature differential of the flow/return to the plate heat exchanger. If there's not much of a temperature drop of the heating water coming out of the plate, then it's going to be blocked up and not transferring the heat.

But, if you're having heating issues also, I'd be checking the pump, sometimes it can be spinning but the impeller bit isn't moving with it.