Radiators getting hot when the DHW is used - Baxi Duetec

[ringi]

I have a Baxi Duetec boiler in a property I rent out and can’t understand what is going on with it.

The tenants told me the radiators were getting hot when their children had a long shower.

I called out my normal gas safe person, he cleaned out the heat exchange and it all seemed to be working, he said there was some bits of rubber in the heat exchange. (I tested it before he left and could not feel the CH pipes getting hot.)

About a week later the tenants informed me that the radiators where once again getting hot when they use the DWP. (I have tested it and can confirm this.)

The heating has not been used in the mean time.

My normal gas safe person says I should get the system flushed, and then get him back to clean out the heat exchanger again. He will not take reasonability for the problem coming back and his “fix” not working.

I can’t understand how a blocked heat exchange would allow the radiators to get hot if the diverter value was working correctly.

I can get bexi to fix the boiler for a large fixed cost this will also give me 1 year of cover.

Thoughts please…..

 

[dave1973]

Your diverter valve is letting by. Basically when your hot water is called the central heating water heated and pumped from your heat exchanger should be diverted through your plate heat exchanger and make a circuit back around your boiler.
If the diverter valve is letting by (not fully closed or crap stuck on seating) the primary heated water will also go down the heating circuit.
Change diverter valve , drain system and fill with fresh water and add a chemical inhibitor. If you can afford to get a magnetic filter fitted too (worth there weight in gold).
People in general never drain there heating system, this should be done every 12 months. Just like when we get our cars serviced and oil changed, I hope!
Hope this helps

Regards

David

 

[ringi]

The system was drain last summer and the water was totally clear at the time, when it was refilled it had a chemical inhibitor added.

I am getting very close to believing that it is the diverter valve regardless of what my GS person tells me.

 

[dave1973]

Diverter valve, common and easy diagnose

 

[ALCPlumbing]

What do you mean you are getting close to believing it's the diverter valve.

It is the diverter valve.

If it was just a case of the plate heat exchanger being blocked then you'd find the main symptom would be overheating due to lack of circulation.

 

[FiremanT]

People in general never drain there heating system, this should be done every 12 months.

Seriously?

Utter nonsense

 

[Tibbot]

My normal gas safe person says I should get the system flushed, and then get him back to clean out the heat exchanger again. He will not take reasonability for the problem coming back and his “fix” not working.

Is this the same gas safe person you describe in your other posts? If so, the reason he's not be prepared to guarantee his fixes may be because he doesn't know how to fix.

 

[dave1973]

FiremanT , seriously drain your heating system once a year and add inhibitor.
I'd say 50-60% of all breakdown I attend are due to dirty systems. Clogged pumps, heat exchangers, dirty sensors/thermisters and diverter valves!!etc etc

 

[picasso]

Drain heating systems every 12 months ? do you have customers willing to pay for this dave 1973 ? I cant imagine why anybody would believe this would be beneficial.

 

[dave1973]

Most customers think a boiler service is more than enough. It's half a job and no most people don't want this done. Until I show the filthy pump that's cost a few quid to replace or the F and E tank full of crap. Then you will hear " you know what I can't remember when it was last drained, I think ABBA was number one at the time!"
Drain down add inhibitor and a magnetic filter and that's looking after your heating system!
Dirty systems have kept me in work for 19 years!

 

[kidgreen61]

People in general never drain there heating system, this should be done every 12 months.

Seriously?

Utter nonsense

What a complete and utter ********

The water in my heating system is as clean as the day it went in 8 yrs ago, apart from the addition of inhibitor.

Sorry FT, my gripe is with idiot, not you

I didn't quote the post very well

 

[dave1973]

Oh my god I've heard it all now . 8 years and your heating system is like mineral water ha ha ha. Must tell the lads at work this one!

 

[Rob]

Regular draining and refilling of a system is one of best ways to cause corrosion and sludge. This is basic stuff.

 

[Agile]

I am getting very close to believing that it is the diverter valve regardless of what my GS person tells me.

If a plate HE is well blocked then as well as the main symptom of hot water going hot/cold then the increased forward pressure will often cause a little leakage through the diverter valve to the heating system.

It seems your engineer does not want to power flush your system or to clean/replace the diverter valve.

Of course all of the full solutions are expensive and he is probably reacting to you expecting that he should do them without being paid any more!

Tony