Boiler losing pressure

[Tatooineghost]

Hi All

I have had a look through some posts and there seems to be a lot of problems with these boilers. Here is my issue.

Background

Ferroli Optimax s35
Megaflo 210
Underfloor heating downstairs with 6 port manifold and 3 zone controllers.
5 Radiator upstairs with heated towel rail in each of the two bathrooms.

Problem is that the boiler will lose pressure. I have not witnessed this, but the boiler will be off and the pressure gauge will be reading either zero or 0.5 bar.
I can refill the system via a filling loop and also the expansion tank via the tyre valve.
This has to be done every other day or so.

My observations.

Once refilled to 1.5 bar, the boiler will light and the gauge will go to 2.0 bar or more and the needle is constantly moving. There is some residue on the red valve cap on the top of the boiler (I assume this is where it vents the pressure, I might be wrong). I have not detected any leaks from the system that I can see.

Radiators and towel rails.
The radiators have rad stats but these do not seem to work, if I turn the rads on they are are hot all the time with no apparent adjustment. The towel rails are always hot, no thermostats.

Mega flow.

The cold fill is hot to the touch and the pipe work says the flow is going in the wrong direction. By this I mean the arrows on the pipe work point the wrong way.

Sorry for the long explanation, but I thought I would let you all know the facts as I see them. Does anybody have any ideas as to why my systems is shutting itself down so often?
Andy thoughts greatly appreciated.
Regards
Andy

 

[kevplumb]

Once refilled to 1.5 bar, the boiler will light and the gauge will go to 2.0 bar or more and the needle is constantly moving. There is some residue on the red valve cap on the top of the boiler (I assume this is where it vents the pressure, I might be wrong). I have not detected any leaks from the system that I can see.

check the prv pipe and have the expansion vessel replaced

 

[twgas]

The red valve cap may be an auto air vent, which is crudded up or a prv, which is not installed correctly/discharging or the expansion vessel which is broke.

The TRVs will not make the rads cooler as soon as you turn them down, they shut off the flow when the room gets to set temp, put them on three or four and leave them alone while the temperature stabilises.

I would advise getting a pro in, with a G3 ticket, to look at the Megaflow if it is indeed fitted wrongly, as you are suggesting.

 

[kevplumb]

Problem is that the boiler will lose pressure. I have not witnessed this, but the boiler will be off and the pressure gauge will be reading either zero or 0.5 bar.
I can refill the system via a filling loop and also the expansion tank via the tyre valve.
This has to be done every other day or so.

then it needs looking at quick as suggested by mick

 

[Tatooineghost]

Hi Guys

Thanks for taking the time to reply. I have had Ferroli out to the boioler, but not for a while. A plumber friend has suggested it may be the expansion tank, so will investigate further.
I will see about getting the pipe work looked at on the Megaflo. I can't believe it can be completely wrong, because it surely would not heat up correctly. What does worry me about the megaflo is the cold inlet becoming warm.

Andy