We have experienced cooler water in both our upstairs showers recently. When turned to full heat they are just about warm enough for a shower (it was about a three quarter turn for very hot water a couple of weeks ago). We haven't changed the amount of time the hot water is set for on our ideal classic boiler - having read other posts could it be an air lock? If so, is there a simple remedy? If not, what else could it be? Many thanks.
Hot water is now just warm in shower
- Thread starter Finchy
- Start date
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has it changed at the taps also?, what is the cylinder stat set to?Has the flow rate altered?
find a thermometer and measure the temperature coming out of the hot tap and the cold tap (not the shower)
also identifying your heating system and tell us if you have Gravity Hot Water or fully pumped; and if you have recently changed your Central Heating usage.
also identifying your heating system and tell us if you have Gravity Hot Water or fully pumped; and if you have recently changed your Central Heating usage.
We have a gravity system and both showers have pumps (one in airing cupboard, one integrated into showers). Central Heating went off at the end of March - we'd didn't have this problem with water temp. last summer when central heating was off. The hot water is set to come on for an hour every morning (again this has been plenty for two of us to shower/wash up, etc. in the past). The flow rate hasn't altered and no obvious difference in tap temperature.
Thanks.
Thanks.
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39C is too cold for hot water. Many people will tell you it has to be 60C to kill Legionella, but anything below 50C is not hot enough.
The next question: Is this because the Cylinder Thermostat is wrong; or the boiler Thermostat, or some other reason?
Is there a thermostat strapped to the side of the Hot Water Cylinder? What is it set to? What is the setting on the boiler thermostat?
Are the shower mixers fed with cold water from a tank, or from the mains? What sort of sink mixer do you have, and how old is it? (this is not a joke). Is there any sign of water dripping from the overflow on the cold water tank?
What controls, pumps, electric valves can you see on the pipes around the boiler and cylinder? If you can post photos that will help.
The next question: Is this because the Cylinder Thermostat is wrong; or the boiler Thermostat, or some other reason?
Is there a thermostat strapped to the side of the Hot Water Cylinder? What is it set to? What is the setting on the boiler thermostat?
Are the shower mixers fed with cold water from a tank, or from the mains? What sort of sink mixer do you have, and how old is it? (this is not a joke). Is there any sign of water dripping from the overflow on the cold water tank?
What controls, pumps, electric valves can you see on the pipes around the boiler and cylinder? If you can post photos that will help.
I have now taken some photos which are attached. The boiler is on its highest setting of 6 (although the boiler servicer said it didn't need to be this high at this time of year I thought it might help). The cylinder thermostat is at 55 degrees. The shower pump picture shows the pump that powers the ensuite shower. The switch for this is the bottom switch in the other photo. The top switch turns on the power shower over the bath.
Not sure if you can see the images - they are saved in the album "Hot water issues"
Thanks.
Not sure if you can see the images - they are saved in the album "Hot water issues"
Thanks.
to add photos to your post, click on the "show my images" link, this will show your thumbnails, you then click on each pic you want
it will then look like
[net]120470/11053_58391459.jpg[/net]
and display
If the cyl stat is set to 55C, and the boiler is on max, then the cyl should heat to 55C before switching off. Try leaving the boiler running for longer, and feel the circulating pipes to see if flow and return get hot within a couple of minutes of the boiler starting. Also feel all the rads to make sure they are cold. You should feel the circulating pump starting to hum, and the pipes in and out of it get equally hot, at once. If the pump is hotter than the pipes it is jammed.
Look for an a motorised valve (3 pipes going into it, squarish metal or plastic head, near the pump.
Bleed the highest radiator in the house to see if water squirts out vigorously - this verifies that there is enough water in the system.
If you adjust the cyl stat with a small screwdriver should hear it click as it turns on and off at the actual cyl temp. You should hear the pump, and possibly the boiler, start and stop as the stat switches on and off.
it will then look like
[net]120470/11053_58391459.jpg[/net]
and display
If the cyl stat is set to 55C, and the boiler is on max, then the cyl should heat to 55C before switching off. Try leaving the boiler running for longer, and feel the circulating pipes to see if flow and return get hot within a couple of minutes of the boiler starting. Also feel all the rads to make sure they are cold. You should feel the circulating pump starting to hum, and the pipes in and out of it get equally hot, at once. If the pump is hotter than the pipes it is jammed.
Look for an a motorised valve (3 pipes going into it, squarish metal or plastic head, near the pump.
Bleed the highest radiator in the house to see if water squirts out vigorously - this verifies that there is enough water in the system.
If you adjust the cyl stat with a small screwdriver should hear it click as it turns on and off at the actual cyl temp. You should hear the pump, and possibly the boiler, start and stop as the stat switches on and off.
The boiler is now running, the pipes are equally hot into and out of the circulating pump (which is humming). The plastic motorised valve is on "W".
The showers are fed from the cold water tank in the loft.
We have recently (April 9th) had a new mixer tap fitted in the basin in the downstairs cloakroom.
There is no dripping from the overflow.
Adjusted the cyl stat back and forth and it does go on and off.
Not confident about bleeding a radiator - they are all cold though.
Thanks.
The showers are fed from the cold water tank in the loft.
We have recently (April 9th) had a new mixer tap fitted in the basin in the downstairs cloakroom.
There is no dripping from the overflow.
Adjusted the cyl stat back and forth and it does go on and off.
Not confident about bleeding a radiator - they are all cold though.
Thanks.
if the new mixer has a cold supply from the main (high pressure) and has an internal leak (this seems more common on ceramic/one lever mixers) it is possible for cold mains water to get into the hot pipe.
If your new mixer does have a mains cold supply, feel its hot pipe and see if it is surprisingly cold. it may/should also have an isolating service valve underneath that you can close, sometimes using a screwdriver.
You can get a radiator bleed key at any DIY or hardware store for a pound or less, it is very easy. it goes in the small square spindle at the top of the side of a rad to let air or gas out. Unless your rads are old and rusty you are not likely to get a leak or anything. You don't take the screw out, you just loosen it a turn or two.
p.s. it looks like you have a modern cylinder, and a modern fully pumped system, so your cylinder should be fully hot within 20 minutes or so. then the cyl stat should click off and the boiler stop even though the timer is on, and stay off for some hours. Check the hot tap temp with your thermometer, then (unless you run the hot tap) the insulation will keep it pretty hot for 24 hours, so turn off the boiler and test the water temp again in a few hours. Also feel the hot water pipe at the downstairs mixer and where it goes into the top of the cylinder and see if they are unexpectedly cold.
If your new mixer does have a mains cold supply, feel its hot pipe and see if it is surprisingly cold. it may/should also have an isolating service valve underneath that you can close, sometimes using a screwdriver.
You can get a radiator bleed key at any DIY or hardware store for a pound or less, it is very easy. it goes in the small square spindle at the top of the side of a rad to let air or gas out. Unless your rads are old and rusty you are not likely to get a leak or anything. You don't take the screw out, you just loosen it a turn or two.
p.s. it looks like you have a modern cylinder, and a modern fully pumped system, so your cylinder should be fully hot within 20 minutes or so. then the cyl stat should click off and the boiler stop even though the timer is on, and stay off for some hours. Check the hot tap temp with your thermometer, then (unless you run the hot tap) the insulation will keep it pretty hot for 24 hours, so turn off the boiler and test the water temp again in a few hours. Also feel the hot water pipe at the downstairs mixer and where it goes into the top of the cylinder and see if they are unexpectedly cold.
OK. The pipe on the downstairs mixer is hot. I turned the cyl stat to 70 and water temp is now 55 - perhaps it had been turned down by plumber who fitted mixer (the timing of his visit does coincide with the drop in water temp. Anyway, boiler is off so I will check temp in a few hours - Many thanks.
The water is no warmer having left the cylinder stat at 70 deg all weekend. The only thing I have yet to try is the radiator bleed - will a diagnosis here mean I don't need to get a heating engineer out or should I call one anyway?
Thanks.
Thanks.
What is the actual temperature of the water in the hot taps? Can you touch the surface of the cylinder, and is it uncomfortably hot, after the boiler has been heating it for half an hour or so? It is possible for cylinder stats to get out of adjustment. Just to check, you do hear the pump start and stop when you adjust the cyl stat and it clicks (with boiler turned on)?
bleeding the highest rad will tell you if there is enough water in the primary circulation. There are a couple of easy fixes, and a couple of difficult ones, depending on what you find. If water does not squirt out vigorously, do you have a Feed and Expansion tank in the loft, and is it full?
If you have a cold-water tank in the loft, is it constantly filling or dripping? (that could indicate a leak)
If you feel the hot pipes leaving the boiler, going through the pump, and going into the cylinder, are they all equally (uncomfortably) hot? If you turn the heating on for a while to test the temperature (you can close most of the radiators) you should find they get "too hot to hold" or "too hot to hold for long"
bleeding the highest rad will tell you if there is enough water in the primary circulation. There are a couple of easy fixes, and a couple of difficult ones, depending on what you find. If water does not squirt out vigorously, do you have a Feed and Expansion tank in the loft, and is it full?
If you have a cold-water tank in the loft, is it constantly filling or dripping? (that could indicate a leak)
If you feel the hot pipes leaving the boiler, going through the pump, and going into the cylinder, are they all equally (uncomfortably) hot? If you turn the heating on for a while to test the temperature (you can close most of the radiators) you should find they get "too hot to hold" or "too hot to hold for long"
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