LMSC If the boiler is heating the supply water to the tank correctly then I would be looking at the thermostat on the tank. Is the thermostat switching off to early. If you check what temperature the tank thermostat is set at and you can adjust the thermostat a bit higher and see if that helps. It would help if you had a thermometer to check the actual water temperature coming out of the taps before and after adjusting the thermostat. Hope this helps
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I agree with @ Meldrew, either the boiler DHW stat or the cylinder stat.
The boiler DHW stat is inside the boiler lower L/H side= cost about £12. I think the boiler needs to be partially drained.
Check the cylinder stat first as Meldrew said.
Thanks folks. I will check as advised starting with the thermostat of the tank. We never changed the setting. It’s set at 55C and the engineer said the other day this is perfect for hot water. It does heat the tank as the water is neither cold nor luke warm. Normally, the water from the tap is hot 15-20 mins after the boiler comes alive. After 30 mins, it is very hot and good for 3 × 4 mins shower.
I will do the before and after test as Meldrew advised and go from there. Will call out the engineer otherwise.
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.LMSC it’s also worth checking timings, if you changed HW to come on with heating (more efficient, but will take a bit longer. Applies to heat only system or system boiler, with single flow temp for HW and CH. Not sure what you have from looking at boiler. Looks like a system boiler where you can set independent flow temps.
They are independent settings and as LMSC has them set they should be just right.
One other thing not connected.👍🏻 It is worth closing the two gate valves and then reopening, they are very prone to seizing which can cause a big problem if you do need to shut them off. Fully open then back ½ a turn👍🏻
Elcarajillo It is worth closing the two gate valves and then reopening, they are very prone to seizing which can cause a big problem if you do need to shut them off. Fully open then back ½ a turn
What’s this two-gate valve please? Where is it located? 🤔
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LMSC These (the red-and-brass bits):
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Worth mentioning that old gate valves have a tendency for the spindle connection to the gate to fracture when reopening.
So be very careful when reopening, do it gently and if it feels stiff, turn it a little in the other direction and try reopening again.
I had to close one to isolate something, and it snapped inside when opening. Fortunately i had a spare ready just in case and had to fit that. Even more fortunately, the upstream valve worked fine which made fitting easier.
Thanks both. I have been trying to keeping them as smooth as possible. But, the 2 and 3 won’t budge. The gas engineers told us a few times all these pipes are bizzare, happens only in very old properties and rarely in those built from 1980. Ours’ were built in 1980.
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You could try backing off the small nut between the red hand wheel and the valve body,this compresses the gland seal onto the shaft, dribble a little WD 40 or penetrating oil onto the shaft and allow to soak. Then try rotating H/W back and forth (just gently). Return small nut afterwards. Could save you trouble in the future.
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Elcarajillo Will do. Those two haven’t budged despite best (careful) efforts. Will keep trying. I think the boiler, water tank and the pipes need sorting out.
One of the engineers already said we need to simplify and update, while another said mega flow as it is a big property. We don’t need a mega flow for a family of 3, do we?
Btw, the hot water ran again for 30 mins. This normally gives hot water, where we can’t set it at max at the shower. With nothing changed, the Gran at home said at noon that she had to keep the tap at max to give herself a hot shower. I running tap hot water temp was about 41C-42C.
Don’t know what had changed. I thought the engineer didn’t check properly and gave us all good test certificate. Perhaps, he won’t know unless we tell him this is an issue now. Shouldn’t the issue, if it is, with that boiler pop up when a routine service is done?
LMSC They won’t be checking motorised valves etc in a boiler service. Perhaps motorised valve is faulty…are any rads apart from towel rails heating when you run the hot water. Is the pipe going to the boiler hx nice n hot e.g 50C
DavecUK …are any rads apart from towel rails heating when you run the hot water. Is the pipe going to the boiler hx nice n hot e.g 50C
We have enabled the living room to come up with moderate rad settings when the temp < 16.5C. Can check this tmrw.
I think the middle pipe is the connection goes into the boiler; the left is the drain and the right is the fill. This is a good point. I will check tmrw morning! Thanks Dave.
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LMSC Sorry my fault, coffee machines on the brain by boiler I mean the hot tank and by HX i mean the long spiral pipe inside it that heats the water. So you have to be in the airing cupboard near the 3 way valve and checked the pipe going into the hot tank is hot enough, or hot as it should be, which would be almost 50C if your boiler is set to output hot water at 55.
I see you have more than 1 motorised valve and something that looks suspiciously like a 3rd on the right of the tank on the floor. I don’t really understand why you would have so many on a simple vented system with a simple system boiler? But hey, what do I know, I’m not a plumber.
Usually though you have a heat source, a pump (which will all be in your boiler), pumping up to a single 3 way valve for HW and Rads. The HW will often run the towel rails and heat the HW tank) the CH position may, or may not heat the towel rails as well….and shared, the third position will send hot water to both. I can only think for some reason they have your hot water on a separate 3 way valve, to try and do something clever with the towel radiators.
If you set the boiler for hot water only, track which valve moves and then source the pipe from there to the HW tank that the boiler is feeding. The upper pipe should be the hot into the tank and the lower one the return to the boiler. You won’t have a feed and expansion tank of course, that will all be inside the boiler and some of them can even have the 3 way valve fitted in the boiler.
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LMSC I think you will find the L/H one is the condensate drain. Centre one gas supply to boiler and the R/h one is the cold feed for D/H water and charging the heating system.
There is also a diverter valve inside the boiler case R/H side towards the back. It is possible if it is partially closed it could be restricting the D/H water flow. It does not need the system to be drained to check the motor and move the lever. (plumber)
Try turning up the D/HW knob on the boiler to max and see if the water from shower / tap is hotter,
Thx Guys!
The 3-way valve, which Dave showed wasn’t as hot as it should. Re-the HW Knob on the boiler, I have taken it to 5.5. The gas engineer did tell me makes no difference to the temp of the water irrespective of where it is set.
However, the temperature control on the hot water bank may be important. I have slightly put it up, which helped. My wife did say this morning the water is hotter than yesterday.
However, I do think there is an issue, which requires investigation . Perhaps, it is one of the valves, which you guys are mentioning. I think I may have to call a gas engineer who will also check the plumbing / mechanical side of things. I don’t want to mess up.
Thx folks!
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LMSC Re-the HW Knob on the boiler, I have taken it to 5.5. The gas engineer did tell me makes no difference to the temp of the water irrespective of where it is set.
However, the temperature control on the hot water bank may be important. I have slightly put it up, which helped. My wife did say this morning the water is hotter than yesterday.
I’d be wary about what the gas engineer says (unless the knob has always been in the position on the photo). That knob looks set to make 70C max, with 60 being the top of the normal range. I’d assume your cylinder stat is set to 60, unless you changed it…you can look and check. As winter approaches and water temp drops 50 may not have been enough for the length of time it was on, sure you moved it up to 55, now try 60 (or 6 on the dial).
P.S The gas engineer might be thinking it will reach what the tank stat is set to. But it won’t if the time is too short and incoming water too cold.
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DavecUK I’d assume your cylinder stat is set to 60, unless you changed it…you can look and check. As winter approaches and water temp drops 50 may not have been enough for the length of time it was on, sure you moved it up to 55, now try 60 (or 6 on the dial).
I never had to change anything since Day 1. The knobs were as shown in the picture above (e) for hot water and at 55C at the cylinder. Either some valve isn’t working as it should or the perhaps we had been letting the hot water run a little longer in the past than we are atm. Perhaps, a sign of aging! 🤣
Sure, I will raise the knob to 6 and/or 60 on the cylinder and see. Thx! 🙏🏽
How does yours’ work please? Thx
LMSC My cylinder stat is set to 60, my water temp (which affects HW and CH, only one control), is set to 55. When the cold weather set in I had to increase the time the HW was on. My intention once I start using the CH in November, is to have the HW on a bit longer still and overlap it with the CH, to get the lowest flow temp drop I can and maximise gas savings. This is for 3 reasons:
- Increased savings from condensing (due to flow temps)
- My boiler can only modulate down to 8.7kW, because like yours, mine is well oversized for the property. I could happily run on a boiler of 15kW, which would then modulate much lower and cycle less.
- Reduced boiler cycling
I had no choice over the boiler size (cos it was free, long story)….had I a choice I would have gone for 15kW (6 bedroom house), for a relatively modern property and double glazing, a powerful heat only boiler isn’t required. Of course with Combis, they have to be more powerful because of the instant hot water….and I don’t like Combis really.