Cylinder wiring

[LondonFoy]

Thanks, not heard of EPH before, I’ll go look. I was reading another post on here about flow rate. Am I right thinking if the flow rate from the HW pump is too slow, then the entire coil won’t get hot, only the top. That way, only the top of the tank gets hot. If the flow is increased, then the entire coil get hot and therefore transfers more heat into a wider surface area of the tank.

…. Which takes me back to my earlier comments about the bottom of the tank is really really cool while the taps are scalding.

It’s got one of those Trident eco/smart pumps…. CP1,2,3, PP1,2,3, speed 1,2,3, Auto/eco and night modes. I note it’s currently on CP3 which gets 33 L/m. The manual speed3 gets 50 l/m.

Just a thought…

 

[Johntheo5]

One might normally expect around 8 to 10C difference between the cylinder top and just above the bottom coil and a little less between the cylinder top and the cylinder stat location. The greater the coil flowrate the greater the heat transfer and less difference between the cylinder top/bottom. Your pump on CP3 will be running at a very high output, feel the coil at the top and bottom and note the temperature difference. Also look for a wheelhead gate valve on the coil return, this, if installed, may be throttling the flow.

 

[LondonFoy]

Yes, cp3 is giving 30-35 litres/minute flow rate. The difference in temp between too and bottom of tank is more like 25c or greater. I’m tempted to drain the tank and crack it open to see how badly it’s scaled up etc. it’s an old open system and the CH was in a shocking state last year before we power washed it, dosed, magnaclean added, pump changed etc. 1 whole loop was almost fully blocked.

This then takes me back to the stat not getting enough temp that far down, if the tanks either full or junk, or the flow is transferring heat at the top, and not sufficiently at the bottom of the coil that might add to the lack of satisfied cutting the HW, as it’s just not getting to temp, hence it having to set the stat so low?

Stat position is right. No gates anywhere, only either side of the main pump. Cold flow from lift tank sufficient diameter for flow input. It’s a 140l Hercal.

 

[Johntheo5]

Some circ pumps give very useful info including the flowrate in m3/hr, does yours show at least the power in watts?, if so, note it, also post any info you may have on the pump like a e manual.

 

[LondonFoy]

This is the one. https://www.tridentpumps.co.uk/product/energy-efficient-pump/

It shows the watts/litres/

 

[Johntheo5]

Well, what is it showing (on HW only) in watts and litres?, its normally litres/min but we can figure that out. I think yours only shows watts , W.