How can I figure out why my water isn't hot when the heating is on

edanto

Until last week I would have hot water when the central heating was on. Now I don't.

How do I start looking into this?

It's a gas boiler, new enough, no settings changed on it.

slavetothegrind

more info, boiler model, is there a motorised valve or trv on the pipe into your hot water tank pictures of your hot press arrangement may help also

perry stanley

As well as previous queries may I ask do you have a means to select either dhw( hot water , only) and CH
(central heating). If not, next hows the heating, any loss / reduction in heat in any of the rads?
Cheers

zxcvbnm12

it sounds like an airlock unless u have motorised valves one cud be gone

crosstownk

What sort of boiler - standard or combi? Do you have a lagged hot water cylinder in the hot press?

edanto

Thanks for the replies. Been out every night this week canvassing and only getting back to this now.

The boiler is a Baxi Maxiflo. I'm afraid I don't know if that's standard or combo. What's the difference?

The (lagged) hot water cylinder is cold - previously is was hot.

There are no pumps anywhere in the system, other than the one by the boiler, and that's working fine.

Rads seem fine, except when I checked them all the top of the small one in the bathroom isn't as hot as the rest - might there be some air in the system?

ps there is an option on the boiler to select just hot water, but it's not set to that - it's set to central heating and hot water. Pressure is at about 1 bar.

thanks all

edanto

Made a mistake in the post above, there isn't an option on the boiler to have hot water only. There are only two pipes from the boiler, a flow and a return.

I'm gonna see if I can find a pump or valve upstairs, no joy yet.

DoneDL

Feel the top pipe or flow pipe to the cylinder and see if its getting hot, if not then its an air lock or closed valve on the flow.

Sparkpea

could also be blocked pipe in the coil

DanWall

There may be a valve near the tank, to regulate the flow through the tank primary circuit, similar to a locksheald valve on a radiator, it may be just a hand valve, try opening it a half turn

pslat

Hi This is the motorised valve on our system (white box). Ther are many makes so it may not look like this one but will have an electric cable attached to it. If the valve is not getting power or is stuck the feed to the coil in the hot tank may not be getting any hot water. In my case there is a small lever (top of box in pic) to overide the valve and it can be activated by slowly moving the lever across the slot to the locking position. If you can find the valve try for a manual lever and see if you get hot water feeding the cylinder coil. Now where did I leave the hoover...

edanto

Thanks for the advice guys, it was much appreciated.

A boardsie was able to come out to the house on Saturday and solve it - there was an airlock in the coil, and he fitted a new air release valve (not sure if that's the actual name for it) and now I'll be able to check for air in that part of the system myself in future.

If there is an ongoing problem with air, I know it points to a bigger problem, for example a possible leak from the gunbarrel that goes from my shed into the house, so hopefully I don't have that!

Thank you all for the advice.