CH pump from thermal store and blender position.

[jasontaz]

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• jasontaz
• 3 Mar 2013
• 1

OK, no comments on the quality of the diagram .
1 = the pump
2 = blend valve
pipes going off the the left = ch system.
the blue arrows are the intended flow.

This is how it has been plumbed. I don't know if blending valve are non-return. The coil is the coil in the thermal store.
My question: is this a valid configuration?

It seems to me that if the water is too hot, then the valve will open to cooler return water, but because of the pump being on the hot flow only, the water will actually want to flow the wrong way down the cold inlet side of the valve to return through the coil and back to the low pressure (inlet) side of the pump. (the green arrow).

There will be no pressure diff to push the cold inlet water into the system.

Can somone explain / verify ....
TIA - I have a few more thermal store / fire questions, but think I should ask them one at a time.

 

[twgas]

Is there a fault ie. does the system work?
Do you have a boiler?

 

[gaspro1981]

Gledhill ??

 

[Onetap]

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• jasontaz
• 3 Mar 2013
• 1

OK, no comments on the quality of the diagram .
1 = the pump
2 = blend valve
pipes going off the the left = ch system.
the blue arrows are the intended flow.

It isn't the way I'd expect to see it done, assuming the 'spiral' is meant to be the thermal store.

The simple answer is to look at the valve to get the manufacturer's name and valve type and then look on the internet for the installation instructions.

One of the 3 ports will always be open and the pump is connected to that.

 

[jasontaz]

Thanks to both. In terms of "3 port", it is a blender, i.e. I think they are designed to limit the outbound water temp by feeding in cooler water (there is a similar think on the water for the hot water taps) i.e. blend not on/off.

I have got a pic of it and am looking it up now. ebasse.
http://infoweb.esbe.se/files/52226/Katalogdel_Termo_GB_99500300_B.pdf
It is a Esbe VTA313.

The PDF doesn't seem to cover radiators and a thermal store. The only one that looks anything like it is fig 1 on Page 116, where the pump is inside the circuit.

The thermal store is a Gredhill Torrent MultiFuelStore SF.

I can't see with the pump before the hot feed, how any water can make it from the return side of the rads, through the blender as the pump is drawing the water through.

Any thoughts appreciated.

 

[Norcon]

That looks more like a hot water secondary circulation loop with the pump fitted incorrectly.
Should be on the return loop with an nrv fitted upstream.

The VTA 313 is designed for potable water.

 

[jasontaz]

I understood all the words, but just not together . Potable = drinking water, I read from the spec that it is used in basin set up and another model is used in heating circuits.

Will it be OK to use the same blender or should I get it replaced?

The return loop: so inside the loop - see purple bit.

So it is definately shouldn't go where it is?

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• jasontaz
• 3 Mar 2013
• 1

And where on my beautiful schematic should the NRV go?[/quote]

 

[Norcon]

The VTA313 is also not designed for sytems with "HWC" according to ESBE documentation.

HWC means Hot Water Circulation.

Gledhill Torrent documentation show details on the secondary circulation loop.
I think Gledhill supply the Oventrop Brawa valve.

So maybe someone has knocked up this other arrangement with the ESBE valve.
In plumbing its important to select the correct components and there after fit them correctly.

Do you need secondary circulation?
If hot water is reaching the taps within 30 seconds then thats fine.

 

[Jackrae]

From a thermal transfer point of view your hot circulation water should enter the TOP of the thermal store, rather than the bottom, where it will meet the hottest stored water. Using the shown flow direction, the colder water in the bottom of the vessel will over-cool the water in the circulation circuit.

 

[Norcon]

The bottom pipe may be cold mains in.

We don't actually know yet if its supplying a heating circuit or a hot water distribution circuit.
Seems a cok up no matter how you look at it.

 

[jasontaz]

Ah, sorry, I should have been clearer. I had diagnosed this down to it definitely being the CH circuit.

I can see my art work is confusing , drawn on my Galaxy Note. In actual fact this coil occupies a much narrower height, above the solar and below the hot water in and around the same height as the gas boiler send / return.

My bottom pipe (left) is the return from the rads. The top left pipe is the rad send. (2) is the ESBE. OK, so looks like I should replace the valve. Now to the place the pump should be positioned (on my diagram).

Aside: Hot water, cold feed T's off and goes into coil and then carries on up to the Hot outlet, through another ESBE and seems to work well. Water hits showers fine, although I think the pressure / flow is a little high as when the tank cools, it is easy to pass too much water through the coil and it comes out too cool, especially when the bottom of the tank is cool. That' s another question I will be asking as I really want to tune the system.

TIA - much appreciated.

 

[jasontaz]

From a thermal transfer point of view your hot circulation water should enter the TOP of the thermal store, rather than the bottom, where it will meet the hottest stored water. Using the shown flow direction, the colder water in the bottom of the vessel will over-cool the water in the circulation circuit.

I thought the idea was for the coldest flow of water to enter at the bottom to take as much energy from the tank as possible. I am pretty sure all my cooler pipes enter at the bottom (cold feed for how water), otherwise you end up with a more uniform temp, but lower than if allowed to "layer". This is all pretty new to me, but the tank is marked up by Gledhill with labels.

TIA
Jason

 

[matt1e]

From a thermal transfer point of view your hot circulation water should enter the TOP of the thermal store, rather than the bottom, where it will meet the hottest stored water. Using the shown flow direction, the colder water in the bottom of the vessel will over-cool the water in the circulation circuit.

I thought the idea was for the coldest flow of water to enter at the bottom to take as much energy from the tank as possible. I am pretty sure all my cooler pipes enter at the bottom (cold feed for how water), otherwise you end up with a more uniform temp, but lower than if allowed to "layer". This is all pretty new to me, but the tank is marked up by Gledhill with labels.

TIA
Jason

If you are taking heat out of the cylinder then you will taking it out of the top connection, if you are putting heat in then you will also put it into the top connection

Are you sure that what you have drawn are rad circuits?
As per Norcons post the bottom may be cold in and the top outlet DHWS out
The pump would be in the correct position for a loading pump but in that case it will/should be a bronze or stainless steel one
What is the model number of the pump
You would be much better off posting some pics

Matt

 

[jasontaz]

Hi, so modified pic from Gledhill catalogue - all rights are theirs and apology for bad updates:

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• jasontaz
• 3 Mar 2013
• 1

The purple box and the blue line are the bits I am talking about (i.e. the blender and its current position). The other line I have updated is that the stove cold (or return to the stove) is at the bottom I think.

I can certainly take pics if that would help. You want the pump / blender?

In my bad diagram you can see that the colder water returning from the rads enters at the bottom and exits higher up as you say (matt1e). The pump looks like normal heating circulating pump (red, 3 "speed" settings).

Thank you all for your patience with this. I'll get a pic of the pump. I am 100% sure this is the CH circuit. The sealed boiler has and an integral pump. The pump I ref has a feed from the thermostat and there are no pumps on the HW.

 

[Norcon]

I'd remove that valve.
It's serving no purpose other than possibly diverting flow back to the store thus preserving the temperature to a degree.

The HW coil should be above that level and be unaffected ideally.

Those pretty diagrams are for illustrative purposes only. They show a three port valve on the flow from the boiler and the connections to the store coil. Again not needed.