Advice/Opinion on Vaillant Boiler and System

[Elmo3000]

Hi

My boiler is serviced each year. Last year it was noted that the pressure was high and the expansion valve was defective and needed replacing. The engineer gave me a price to supply and fit and I gave him the go ahead. However, pandemic kicked in, have chased the engineer who says he is ultra busy and can't get back there just yet.

I called Vaillant and arranged a one off fix - they have come out and said nothing wrong with the boiler but the radiators need flushing. The radiators are cold at the bottom and warm at the top.

Assuming this is the correct diagnoses, would a flush cure the high pressure and resolve the issue with the expansion valve?

I don't want to throw good money after good money - I just want the correct fix.

 

[terryplumb]

What exactly is your " high pressure problem "?

 

[Elmo3000]

The boiler has to be frequently repressurised.

 

[ianmcd]

your expansion vessel just probably needs re-charged

 

[terryplumb]

Then you are losing pressure . What did the vaillant engineer diagnose the cause of the pressure loss to be?
And does your pressure rise to around 3 bar when central heating is running ,if so the expansion vessel is not performing as it should.

 

[Elmo3000]

The Vaillant Engineer - said there was nothing wrong with the boiler and the problem is the radiators need flushing. Yes, the pressure does rise when the heating is running.

 

[terryplumb]

What does it rise to ? Some pressure rise is normal ,but upto 3 bar is not.

 

[Harry Bloomfield]

Heat rises, it is normal at times for radiators to sometimes be hotter at the top than the bottom. Point is, is that the usual state of affairs?

 

[Elmo3000]

I can't check at the moment, but I am pretty sure it has been around 3. I am at work at the moment but as soon as I get back, I can double check it.

For the moment, should I book in a power flush and if the pressure problem persists, get Vaillant out again?

 

[terryplumb]

No. From what you have told us the engineer is an idiot.
Pressure rises to 3 bar ,system loses pressure and needs topping up frequently ,and engineer tells you there is nowt wrong with the boiler !!
Really ?

 

[Elmo3000]

No. From what you have told us the engineer is an idiot.
Pressure rises to 3 bar ,system loses pressure and needs topping up frequently ,and engineer tells you there is nowt wrong with the boiler !!
Really ?

My exact thoughts. Why would my own gas safe engineer tell me the Expansion Valve needs replacing if it didn't? I wish he had changed it when asked, perhaps I wouldn't have this problem now. He got extra busy because of the pandemic and couldn't get back.

 

[Harry Bloomfield]

Pressure can be lost if the Expansion Vessel has failed, their is a leak somewhere in the system, or if the expansion vessel needs recharging (blowing back up) with air. The usual sign of the latter, is water being expelled from a pipe to outdoors as the the Pressure Relief Valve opens. That is easy to check, just put and seal a plastic sandwich bag over the end of the pipe, with an elastic band.

The EV uses a Schrader type tyre valve and can be easily repressurised with an bike or car tyre pump.

If you bleed a radiator and catch some of the water, what colour is the water? In a well maintained system it should be perfectly clear and inhibitor will have prevented radiators rusting from the inside and protected your system from being choked up with the debris.

 

[terryplumb]

Have you paid vaillant ? For the fixed price repair ? What did they repair ?

 

[Elmo3000]

Have you paid vaillant ? For the fixed price repair ? What did they repair ?

They haven't repaired a thing. Just came into the house said there was nothing wrong with the boiler the problem is the radiators. The repair cost is £51 per month for six months. I am seeking information here, before I go back and complain. Although I went through Vaillant, I believe the cover is via D+G.

 

[Harry Bloomfield]

Which Vaillant model - is the EV in the boiler case?