Hot water not so hot

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just an afterthought while you have the lockshield closed try bleeding that pipe


with the flow open
if it is air or crud t may well force it out :idea:
 
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Haven't tried bleeding with the lockshield closed as yet but I've tested the hot water with the lockshield both closed and one turn open.

In both cases, with the tap stat head off (and pin fully up) it seems as if the flow and return pipes ARE giving the 10 degree difference in heat although the flow seems much hotter than 70 degrees.

Lockshield closed and left overnight (with boiler on all night) I managed to get close to a third of the cylinder with hot water.

Lockshield one turn open and left during the day (with boiler on) the water is still warmish.

So it seems as if hot water IS passing through the coil but is not heating the hot water efficiently (slight understatement), particularly if some of that hot water is diverting down the bypass pipe (when the lockshield valve is open).

This, in my limited understanding, is sounding more and more like an airlock or crud. Correct? Is it advisable to leave the lockshield valve closed all the time - what purpose does it serve?
 
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You can close it. Its only to increase teh flow through the boiler but it probably is fine as it is.

This micraversion is a conversion from direct to indirect cylinder.

I think they were rated at about 2 kW but that was under ideal conditions!

Its probably well scaled up now.

Your 10°C differential indicates the flow is correct and its heating the water. There is no evidence of anything wrong but scaling up is not being fully tested. Nevertheless its losing heat and heating the water, albeit slowly.

I have asled a lot of questions about pumps but dont seem to have any answers!

The Micraversion is designed to be pumped! I dont yet know if yours is !

Tony
 
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As far as I know I've only got the one pump next to the boiler. Motorised valve? Not sure what I'm looking for there. I check the setup fully tomorrow and report back.

Thanks for your help so far Tony, Kev and the others who've replied.
 
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I've looked at everything and I'm pretty sure all I have is the one pump and no motorised valve. It looks like a pretty manual setup.

From the boiler I've got a pipe going to the pump - which is a Two Speed Grundfos Super 4. Above the pump the pipe branches into two. I'm guessing these two pipes are for the hot water and central heating. Each pipe has a lockshield valve with a red wheel on it.

As mentioned in the original post, the (very basic) timer by the hot water cylinder has three settings - on, off and timed. The times are set on a dial allowing setting of two time periods during the day for the hot water/central heating to come on. We simply turn all radiators to minimum in the summer if we only want hot water. I suppose the alternative would be to close the relevant lockshield valve above the pump.

The previous occupant was an old lady who had lived in the property since it was built in the 1950's. I presume she would have wanted central heating most of the year, hence the basic setup.
 
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FWIW this is whats inside your cylinder

88e4_1.JPG


now add 20 years of scale :eek:
 
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Thanks for all your help. I've been away for a week but I'm arranging to get a mate in to descale the system.

Final question regarding the thermostats - just so I understand my system.

I was trying to understand why my boiler wasn't always firing up even on it's highest setting. I presume this is because the boiler thermostat detects that the water going around the primary circuit is at the desired temperature (set on the boiler) so it doesn't need to come on any more until the water begins to lose heat? So radiators will work and the flow pipe into the cylinder is hot - which is the case? Correct?

But I don't understand fully how the tap stat and the detector on the cylinder works. Does it just close the flow of water when the detector detects the temperature of the water in the cylinder has reached the required temperature (i.e. the setting on the tap stat head)? As the water in my cylinder is not heating up correctly due to limescale then my detector will never close off the flow of water. Correct? It's just that I've read about other cylinder thermostats that link to the boiler but I don't see how that would be the case with my antiquated system.

Thanks guys.
 
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But I don't understand fully how the tap stat and the detector on the cylinder works. Does it just close the flow of water when the detector detects the temperature of the water in the cylinder has reached the required temperature (i.e. the setting on the tap stat head)? As the water in my cylinder is not heating up correctly due to limescale then my detector will never close off the flow of water. Correct?

yup

It's just that I've read about other cylinder thermostats that link to the boiler but I don't see how that would be the case with my antiquated system.

thats electrical with a motorised valve

yours is mechanical ;)
 

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