Vokera Mynute HE Pressure Issue

[Tom Simmons]

I have a Mynute 15 HE that is about coming on for 7 years old. It's providing the heating and the hot water via a hot water tank, no cold water header tank.

The problem I have is it used to sit happily for months on end at about 0.5 bar when cold, rising to about 2 bar when running.

Now it keeps subsiding, for instance it is now registering about 0.25 bar when cold, despite being topped up to nearly 1 bar last week. It still reaches 2 bar when running.

I have no sign of a leak anywhere that I can see.

The only other strange thing I am aware of is the kitchen radiator is a double skin and on one rad you can completely remove the bleed plug and not get a drop of water out of it.

Any help gratefully received.

Tom

 

[Riley]

Are the valves to your radiator blocked or is there a leak from it going under the floorboards.

 

[Tom Simmons]

The radiators are all warming up.

All pipes are either in the walls (new build timber frame,stud and dry line) or possibly the ceiling and there's no sign Of any dampness.

Tom

 

[ShaunCorbs]

How old is the property?

 

[Tom Simmons]

6.5 years, I got it from new.

 

[ShaunCorbs]

I would say you need to get a gas safe engy out to check the boiler make sure it's not leaking internally etc

 

[townfanjon]

Any water out of the pressure relief valve ? should be outside, near or behind the boiler .

Radiator vent hole may be blocked , with the heating off just see if you can push a thin piece of wire or a thick needle in it .

 

[Tom Simmons]

When you say outside, do you mean outside of the boiler casing or outside of the building? The only thing that exits the building is the balanced flue.

Under the boiler (its on the wall, fully visible) you can see the gas feed, and 2 or 3 other pipe circuits. Behind some facing board there's the refill line and a coupe of others.

Next to the hot water tank upstairs I think there is at least one of the plastic bucket arrangements that allow you to see when an overflow is occurring. Other than that the rest of the pressurised circuit is under a cover on top of the hot water tank.

 

[jtsplumbing]

Must have a unvented cylinder ! when was the last time any of this was serviced (need a G3 engineer for tank)

 

[townfanjon]

Have you a red expansion vessel in the cylinder cupboard ?
We could do with some pics

 

[Tom Simmons]

As requested, some photos

 

[Tom Simmons]

Meant to say, that I checked the over flow inspection (plastic bucket I referred to previously) that you can see between the left most insulted pipe and the left pressure vessel and there is no sign water has been through there.

I'm guessing that white pipe on the right under the boiler must be the pressure release from the boiler?

Tom

 

[Tom Simmons]

I know it's been a long time since I started this thread, the issue seemed to disappear, however now it's back!

However, I have figured out a couple of things since I originally posted.

1. The disappearance and return of the issue coincide with the stopping and starting of using the heating
2. I've found the pressure release pipes outside, they are at ground level, well lower as they are in the gravel (large pieces) around the house
3. I did find a small leak on the towel rail (on the exit side), so to rule this out I closed the inlet and the lock valve - the leak being between the lock valve and the towel rail. The leak has stopped, the pressure issue hasn't
4. The system is over due a fernox refresh by about a year

The correct working pressure is still reached on either hot water or heating runs, but the pressure now drops to 0.25 bar or less every day or so with the heating on.

Tom