Do I need to keep hydronic hot water cylinder?

jesling

Apologies if this question has already been answered, I did have a poke around but couldn't find anything.

I'm livimg in a 30 year old house that had a hydronic heating system installed at the time of the build. It has had a few modifications over the years but basically remains the same. The heat source is via a slow combustion Wamsler stove with a wet back, max output of 17kw. It services 5 double radiators and a 200l domestic hot water cylinder.
We have now moved our domestic hot water heating to heat pump hot water and would like to remove the old hydronic hot water cylinder all together as it takes up a huge amount of room in our pantry.

I have sought local advice from a number of tradesman and so far one has said that it's not a problem to remove it and another said it was vital to keep it as it acts as a heat buffer, or something, another wasn't sure!
Any advice on this would be much appreciated. Sorry if I haven't provided sufficient information here. Please let me know if that's the case and I'll provide additional details and photos.

Many thanks,
Jonno

nicholas bonham-carter

I am not familiar with the Wamsler stove-is it like the Aga, capable of heating food, and people?
Unless the stove contains a sufficient volume of water in it, I would say that the hot water cylinder is needed to make sure there are no lags in hot water production during periods of high use. The cylinder may not have to be in its present location, and moving it may give you the extra pantry room you desire.
Pictures would be very helpful.—NBC

hot_rod

A wood fired cook stove? It would be a good idea to have a bit of a buffer on a stove like that as they respond slow and your DHW use may not match the stove use?

jesling

Thanks for the replies. Yes, it's similar to an Aga. We predominantly use it for heating our radiators but also do a little bit of cooking. We no longer draw hot water from the cylinder as we now have heat pump hot water.

Is the risk that if the cylinder is removed from the system that the boiler in the back of the stove will run too hot? If so, could this be offset by installing larger radiators?

nicholas bonham-carter

I wonder if this is an open system, in which the potable hot is interconnected with the hot water heating side. This might act as a buffer to store heat for the radiators, and its removal might cause upset the evenness of heat. If this is so the system may be a breeding ground for Legionella bacteria, which can be dangerous, if you use the water for showering.
Can you get some information from the manufacturer, or importer of the stove as to whether the tank is necessary for the operation of the heating side?—NBC

hot_rod

looks like a conditioner chemical was added? Keep that fluid away from potable water. A double walled HX if you do

jesling

Thanks again for the replies. I have drawn a diagram of the system which is probably what I should have done first! Let me know what you think.
I'll try contacting Wamsler as well and see what they think.
Cheers,
Jonno

nicholas bonham-carter

If that stove is a wood, or coal-fired model, then a buffering tank would be a benefit; however the present piping does not seem to use the cylinder for such purpose.
Is your wood, or coal supply so easily available as to make such a fuel choice convenient? Is there gas available? A modern wall-hung condensing boiler would allow for the relocation of all the heating hardware elsewhere, giving you more kitchen, and pantry space, and keep the kitchen cooler at Christmastime as well!—NBC