Woodpellet boiler woes

lostinrates

This is an amzing post, thank you. I will go through your points and respond to them. There were two coils originally, but the ch coil was removed in the rep plumb in effort to solve the issue.

There are two thermostats o. The tank, one high, one low. Have to admit, I tend to just check the top one.


The plumbing runs through a concrete floor, but we can see how long it takes to surface.

Johnandabby

It sounds to me that the heat exchanger within the thermal store isn't larger enough - this means that the cold water passing through doesn't get up to temperature unless the store is at a very high temperature itself. Hence the installer's comment re not turning taps on full - slowing the water flow through the exchanger results in higher output temperature, but obviously not sufficient for your needs if the bath gets cold in the process. You quoted 350 litres of hot water in the coiled tube, but unlikely to be anywhere near this - there will be a small volume of water within the tube, but the rest is just heated as it passes through.

The thermal store acts as a buffer vessel to prevent the boiler having to turn on and off all the time - a 500 litre store is going to take some time to heat up, but a 28 kW boiler should be sufficient. It sounds like the temperature at which the boiler kicks in to reheat the store also needs to be raised.

Personally I think it could be both issues, but I would be interested in hearing what your expert says. I would have put in a separate buffer vessel for the boiler and then a standard hot water cylinder - I've lived with thermal stores before and haven't been completely satisfied. It shouldn't be a 10-point procedure to run a bath!

lostinrates

Thanks, this is all so helpful.

It's making be feel less incompetent because these are all the same queries we made and have been dismissed over!

Yes, we were told once the '350' litres (how much they told me was in the coil' runs out that water is heating by passing through, and we were told in practise thiis would give ' unlimited' hot water. Which always seemed optimistic, but the spec was to cover four bathrooms in use by six double bedrooms.

Fwiw, no hot water at all yesterday or this morning, though the house is lovely and warm.

lostinrates

Update.

Independant expert has confirmed the boiler is adaquately sized but suggests that plumBing mIght not be right, an expansion tank might be faulty and that the settings are wrong. . Is returning with a plumber in February.

bernithebiker

Sounds like a pump/piping/pressure problem to me.

We have a 44kw wood boiler with 2000 litres of buffer tanks. Max boiler temp is 88'c.

But when boiler and buffer tanks are below 60, we obviously cannot get our dhw above 60.

Therefore, not only do we have a 200l immersion as a 'backup' supply, but we have also kept our fuel boiler which fires up if dhw falls below 60.

lostinrates

bernithebiker wrote: »

Sounds like a pump/piping/pressure problem to me.

We have a 44kw wood boiler with 2000 litres of buffer tanks. Max boiler temp is 88'c.

But when boiler and buffer tanks are below 60, we obviously cannot get our dhw above 60.

Therefore, not only do we have a 200l immersion as a 'backup' supply, but we have also kept our fuel boiler which fires up if dhw falls below 60.

Is yours wood or wood pellet? I understood (perhaps incorrectly) that the appropriate ratio size of buffer tank was greater for a wood rather than wood pellet?

We are advised the max safe boiler temp is 80 degrees for our model, but higher for the cylinder (but that it is optimum to keep them at around 75 degrees, perhaps greater on the cylinder)

I would love to have sixty degree hot water. .

Sadly things seem to be unresolvable amicably and we have taken the decision to step things up a gear next week. It's very, very regretful though. We have neither heating nor hot water ATM now...the cylinder is simply unable to maintain its temperature now when any demand t all is placed on it.

bernithebiker

lostinrates wrote: »

Is yours wood or wood pellet? I understood (perhaps incorrectly) that the appropriate ratio size of buffer tank was greater for a wood rather than wood pellet?

We are advised the max safe boiler temp is 80 degrees for our model, but higher for the cylinder (but that it is optimum to keep them at around 75 degrees, perhaps greater on the cylinder)

I would love to have sixty degree hot water. .

Sadly things seem to be unresolvable amicably and we have taken the decision to step things up a gear next week. It's very, very regretful though. We have neither heating nor hot water ATM now...the cylinder is simply unable to maintain its temperature now when any demand t all is placed on it.

Ours is wood logs, not pellet, so you are right, bigger tanks are needed for us.

The whole lot (2000 litres + the boiler itself) can go up to about 86'C max, then it goes into Pause mode, until it's cooled by about 10'C.

A shame your issue isn't resolved. In the past, with this kind of thing, photos of pipework, pumps, etc. have been very useful, as sometimes you can get a Eureka moment where someone notices a pump has been installed upside down!

lostinrates

bernithebiker wrote: »

Ours is wood logs, not pellet, so you are right, bigger tanks are needed for us.

The whole lot (2000 litres + the boiler itself) can go up to about 86'C max, then it goes into Pause mode, until it's cooled by about 10'C.

A shame your issue isn't resolved. In the past, with this kind of thing, photos of pipework, pumps, etc. have been very useful, as sometimes you can get a Eureka moment where someone notices a pump has been installed upside down!

There is nothing I would like more, with my frustration and the excellent advice I have recieved from people here, than to share pictures.

ATM things are very sour and i thing I have been right to be guarded as it looks as if it will be impossible to avoid this becoming contentious. The last thing I want if that happens is for the suppliers to find this and say I have been dragging their name through the mud. I have been very careful, I hope, to give them every chance, because I believe it is ultimately the best solution for all of us if this remains 'amicable' and they get it functioning.

Canucklehead

I would suggest you use the MCS facility to resolve your problem.

Is the boiler manufacturer of such poor quality that they cannot give you system design advice? Or any other advice for that matter.
Has the installer consulted the manufacturer?

It would seem the boiler and store are not talking to each other to maintain temp.

It's possible the store is some 200 litres undersized.

25 litres / KW = 700 litres

Do you have temperature blending valves on the c/h and dhw flows?

lostinrates

Canucklehead wrote: »

I would suggest you use the MCS facility to resolve your problem.

Is the boiler manufacturer of such poor quality that they cannot give you system design advice? Or any other advice for that matter.
Has the installer consulted the manufacturer?

It would seem the boiler and store are not talking to each other to maintain temp.

It's possible the store is some 200 litres undersized.

25 litres / KW = 700 litres

Do you have temperature blending valves on the c/h and dhw flows?

Thanks Canucklehead, I believe the installer has contacted the manufacturer. The manufacturer actually did attend to see the installation last year and thought it looked ok. Since then it has been relumbed because it wasn't ok.

The boiler seems to be getting the message from the cylinder...it's often on its highest power (though not at it's highest temperature).

The problem with us speaking direct to the manufacturer is, as I have clearly demonstrated, our knowledge is minimal! We need to have another professional involved who can act on manufacturer's advice, of that I am certain.

This is the first time the store being undersized has been suggested, though one of the remedies we have considered when only hot water was a problem linking a second store for the store of hot water for baths/showers/ kitchen use etc without challenging the first tank.

I have now taken advice (on legal aspects from a consumer point of view rather than on just the heating!) and we are acting on that, but I have emailed the linked complaint procedure to my 'team' and it might well be a better way to persue this. Thanks again.

I am so grateful for all the steers I have been given here, just getting a better understanding is helping me keep up a bit better with discussion about the system works and the influences on it.