Combi boiler, can't get a good shower without heating on

penguine

We have a combi boiler which is about 7 years old and serviced every year by British Gas. When the heating is on our showers are great, when it's not we're alternately scalded and frozen.

We're trying to delay turning on the central heating for as long as possible as last year's bill was horrendous. But it takes ages to have a shower in the morning because we have to stand out of the water while it goes from one temperature extreme to the other, and constantly adjust the hot tap.

I've asked British Gas to adjust the water temperature when it's serviced but this never seems to help.

Is there any way we can get a good shower with this boiler, or is it a lost cause?

fat-tony_4

penguine wrote: »

We have a combi boiler which is about 7 years old and serviced every year by British Gas. When the heating is on our showers are great, when it's not we're alternately scalded and frozen.

We're trying to leave off turning on central heating for as long as possible as last year's bill was horrendous. But it takes ages to have a shower in the morning because we have to stand out of the water while it goes from one temperature extreme to the other, and constantly adjust the hot tap.

I've asked British Gas to adjust the water temperature when it's serviced but this never seems to help.

Is there any way we can get a good shower with this boiler, or is it a lost cause?

I had a similar problem about a year ago. It's wasn't the water temperature that's the problem. It's a valve type thing in the boiler, it gets "gunked up" and when the water heats up it overheats and trips the gas out, for some reason it doesn't happen when the heating is on . Think that's what the plumber told me. He fixed it and it now works. I have no idea if that's something that whould be dealt with in a service.

myhooose

Do your radiators get warm when the shower is on? If so, it sounds like the problem I had. The diveter valve is leaking some of the heated water (in a closed loop) into the central heating system. The seals or the whole diverter valve need to be replaced, it cost me about £250 to have fixed.

penguine

fat-tony wrote: »

I had a similar problem about a year ago. It's wasn't the water temperature that's the problem. It's a valve type thing in the boiler, it gets "gunked up" and when the water heats up it overheats and trips the gas out, for some reason it doesn't happen when the heating is on . Think that's what the plumber told me. He fixed it and it now works. I have no idea if that's something that whould be dealt with in a service.

Did your boiler shut off altogether? Ours doesn't, it just can't maintain a constant temperature. I've also wondered if a different shower mixer would help, or are they all pretty much the same?

penguine

myhooose wrote: »

Do your radiators get warm when the shower is on? If so, it sounds like the problem I had. The diveter valve is leaking some of the heated water (in a closed loop) into the central heating system. The seals or the whole diverter valve need to be replaced, it cost me about £250 to have fixed.

I don't think our radiators get warm when the shower is on, but I'll check tomorrow morning to be sure.

mopsey

Some older combi boilers simply haven't the capacity to heat your shower water and also the c/heating at the same time.
If it's 7 years old it's a pensioner in combi terms!!
Have you thought about fitting a thermostatic shower valve? It would be cheaper than a new boiler.

twinklefish

I had the same problem with the shower in my old flat. I was all for swapping out the mixer shower for an electric but my plumber just popped the front of the shower control off and there was a large plastic screw inside which he adjusted I think it had something to do with regulating the flow of hot and cold to get a better mix.

I had no problem after that so it could be something that simple.

Tx

penguine

mopsey wrote: »

Some older combi boilers simply haven't the capacity to heat your shower water and also the c/heating at the same time.
If it's 7 years old it's a pensioner in combi terms!!
Have you thought about fitting a thermostatic shower valve? It would be cheaper than a new boiler.

Actually, it's fine when the central heating is on. The problem is that we can't get a decent shower when the central heating isn't on!

Will look into the thermostatic shower valve though, don't suppose it could hurt.

penguine

twinklefish wrote: »

I had the same problem with the shower in my old flat. I was all for swapping out the mixer shower for an electric but my plumber just popped the front of the shower control off and there was a large plastic screw inside which he adjusted I think it had something to do with regulating the flow of hot and cold to get a better mix.

I had no problem after that so it could be something that simple.

Thanks, I'll look into that.

fat-tony_4

penguine wrote: »

Did your boiler shut off altogether? Ours doesn't, it just can't maintain a constant temperature. I've also wondered if a different shower mixer would help, or are they all pretty much the same?

No it would just run hot then cold, then hot then cold, unless, like you, the heating was on, when I would have a nice consistently hot(actually very hot as I thought the problem was in the water temperature setting on my boiler so had it very high) shower. Do you have a similar problem when running hot water in general?

fat-tony

penguine

fat-tony wrote: »

No it would just run hot then cold, then hot then cold, unless, like you, the heating was on, when I would have a nice consistently hot(actually very hot as I thought the problem was in the water temperature setting on my boiler so had it very high) shower. Do you have a similar problem when running hot water in general?

fat-tony

That sounds very much like our problem. When running hot water from taps (rather than the shower) it gets very hot when the central heating is on, otherwise it just takes a long time to get hot (not fluctuating back and forth tho like the shower). I will look into the valve thing you mentioned, that sounds promising. Thanks again.