Anyone know about combi boilers? What is the red tap for?

[marmitesharmite]

This morning our hot water and heating were off. I checked the boiler and the pressure had dropped through the floor, so I re-pressurised it using the blue taps. I've done this before. The hot water came on ok, but not the heating. I checked the radiators and they don't need bleeding. I've got an engineer appointment for Wednesday, so we'll need to freeze until then. However, I've suddenly thought that maybe when I re-pressurised the boiler, I was still half asleep, so might have turned the red tap by mistake. Does anyone know what it's for and whether it should be horizontal or vertical?

If it is horizontal it is closed, that is all I can tell you

Calling @pigletjohn

Hopeful bump.

You Tube is your friend......everything is on there! Check it out

If it did repressurise ( can you see the pressure gauge?) then you must have used the right one initially ( I’m jealous of your tap- I have to get a screwdriver and turn a tiny screw in the back of the tank cupboard).

Hi Hallmark. Yes, it is repressurised, and we're getting hot water, but no heating.The odd thing is that there are no error codes and the boiler display and thermostat both says that they're "on", and the boiler sounds like its running (i.e. heating something) but the radiators aren't getting warm. It does seem logical that there might be a blockage somewhere, but not in the radiators. That's why I wondered about the red tap, especially if horizontal means it's closed. I could just turn it the other way, but I'm worried about experimenting.

I've tried searching for the answer online but not getting anywhere so far. I have the boiler installation manual too, and that's not helping. I think the red tap may be part of the filter, which is installed separately, so that is my next bit of research. But a plumber may be able to tell me the answer in a heartbeat!

Are the pump and valves working correctly, ie does it sound like hot water is moving through the heating system?

That red tap is off. When you look at ideal filter system images on Google the red taps are on.

idealheating.com/uploads/documents/installation-manual-ideal-system-filter.pdf

I've taken the plunge and turned the red tap to vertical. .... The radiators are now heating, so I'm cautiously celebrating, but keeping a nervous eye on it. The pressure guage rose, but seems to have stopped just below 2 bar. Fingers crossed it's sorted. But I can"t believe there isn't a simple way of verifying which way the taps should be turned for normal operation.

Basically I think it should be on and that’s why the water isn’t getting through to the rads. Hence why boiler is fired up but no heating.

Im not a plumber or boiler engineer though.

If the radiators worked before, I would be wondering how the tap got turned off.

Thanks, yes, I found that, but it didn't say what I wanted to know. Once I realised it was part if the filter, it seemed logical that the tap should be in the "open" position, so I assumed "righty tighty, lefty loosey", crossed my fingers, and turned it.

looks like the red tap is to control the supply to the heater circuit as it leads to the filter, which is used to remove any crap that might block radiators etc.
looks like you managed to turn off whilst re-charging the boiler.

Yes, that's my conclusion too.😳 I was still half asleep and, as I've repressurised the boiler several times before, I was on auto-pilot. But my brain must have got disconnected from my hands!

The pressure does seem high now though, since turning the tap, so I'm keeping an eye on it. Not sure if that's a problem or if there's a way to reduce it, other than maybe by bleeding a radiator, so will look that up.

I haven't had time to watch this video, but this might help?

Just to confirm the red tap is an isolator for the filter so it can be removed for servicing without draining the system.

Generally the open position is in line with the pipe for all valves.

If the system is hot a little over 2 bar is within normal range though a little on the high side.

Cold it should be around 1.25 bar

Keep an eye on the pressure, if it continues to drop you may well have a small leak somewhere.

Thanks @Surplus2requirements . I've managed to reduce the pressure by bleeding a radiator, so it's now more normal.

It's generally a trouble free system, but approximately once a year we wake up to no hot water/heating and the boiler pressure has dropped to zero, as if there had been a sudden big leak rather than a slow gradual leak. However, there is never an obvious sign of a leak, and when I re-pressurise the bolier (correctly 🙂) it usually goes back to normal.

I did wonder if these low pressure events might relate to some sort of mains leak outside the boundary of our home but, if so, the neighbours would be waking up to no hot water/heating too. So it's still a bit of a mystery.

It may be something going adrift inside the boiler but won't be related to anything outside because it a closed system that you pressurise from the mains and then isolate from it.

Just turn red tap so it is vertical.

Have you tried that already ?

Yes! You've inadvertantly turned off the central heating flow by rorating the red tap! It needs to be vertical, as does the blue return one on the other side, otherwise no hot water will flow through the radiators & you could damage your boiler...