Adding thermostats inside Hotpress

lastbuilders

Hi,

I am nearing the end of a self build and am considering adding a thermostat inside the hot press. This is because it gets very hot when the heating is on for more than a few hours.

I think there needs to be a valve put on the cylinder that will close when the water gets to a certain temperature as currently the water passes through the cylinder continuously when the heating is on.

Can anyone let me know what is involved with adding such a valve? The plumber has finished his 2nd fix so it would need to be retrofitted. there are currently 2 zones in the heating system. One for upstairs and one for downstairs.

Lastbuilders

311

If your system has two zone valves ,you'll need to install a bypass along with the thermostat.
Myson are the best at the moment ,they make a manual thermostat that needs no power .

I won't type my trade away ,any plumber will tell you what a bypass is .

crosstownk

I'm not a plumber, so excuse my ignorance, but would it not be possible to put a motorised valve, controlled by the cylinder stat, on the feed to the HWC?

311

Theres absolutely no need for a motorized valve for hot water temperature control ,it's very expensive to do it that way.

The mechanical one by myson ,has a stat that goes against the cylinder and the heat acts to charge the valve to close. This means the only power you need to run the boiler is the pump ,gas valve ,fan.

The only reason I'd install a motorized valve for hot water control ,would probably be a 3 port motorized valve ,which would control the boiler to come on when the temperature dropped ,making sure you always had hot water.

crosstownk

_Brian_ wrote:

Theres absolutely no need for a motorized valve for hot water temperature control ,it's very expensive to do it that way.

I see what you mean - let the boiler stat control the HWC temp. But is there any economy to be gained, in the long term, by having a HWC stat set lower than the boiler stat?

311

crosstownk wrote:

I see what you mean - let the boiler stat control the HWC temp. But is there any economy to be gained, in the long term, by having a HWC stat set lower than the boiler stat?

Sorry crosstownk ,you've got me wrong. Having a seperate thermostat on the cylinder is not only economical ,but safer aswell.
The valve I am talking about does the same job as a motorized valve ,except it needs no electricity to work.

The reason I say the water is safer ,is because during the winter months when the heating is on a lot more ,without a thermostat fitted to the cylinder ,sometimes the water will get way too hot.Especially when there are kids in the house.

It's actually a standard (Bord Gais) now on installations that a thermostat be fitted ,when a new boiler goes in:)

crosstownk

_Brian_ wrote:

Sorry crosstownk ,you've got me wrong.

Yep sorry _Brian_ - I misread that alright - thanks for clarifying it.

davidoco

lastbuilders wrote:

I think there needs to be a valve put on the cylinder that will close when the water gets to a certain temperature as currently the water passes through the cylinder continuously when the heating is on.

The Myson non electric valve is a neat simple solution but maybe you need to look at your hot water requirements. For example there should be no need to be heating a full tank of water after 8 or 9 in the evening which will happen when you heating is on somewhere else in the house.

What you should consider is added another zone valve to the cylinder flow, a bypass valve unless you have one or two rads without TRV, and a three channel clock - Horstmann do a neat one call ChannelPlus which offers a boost facility. You can then set your water to heat for x hours in the morning, x hours in the middle of the day, x hours in the evening together with a nice boost feature for 1 or two hours - or whatever your hot water needs are.

Reyman

_Brian_ wrote:

Sorry crosstownk ,you've got me wrong. Having a seperate thermostat on the cylinder is not only economical ,but safer aswell.
The valve I am talking about does the same job as a motorized valve ,except it needs no electricity to work.

The reason I say the water is safer ,is because during the winter months when the heating is on a lot more ,without a thermostat fitted to the cylinder ,sometimes the water will get way too hot.Especially when there are kids in the house.

It's actually a standard (Bord Gais) now on installations that a thermostat be fitted ,when a new boiler goes in:)

I must be out of date on this. I thought that the hot cylinder coil was regarded a safety heat dispersion sink in the heating system. I.E. in an overheating situation it would always dissipate heat and couldn't be blocked by someone who didn't know what they were doing
But I'd be pleased to hear I'm wrong, because I don't like heating water for no reason either

davidoco

Reyman wrote:

I must be out of date on this. I thought that the hot cylinder coil was regarded a safety heat dispersion sink in the heating system. I.E. in an overheating situation it would always dissipate heat and couldn't be blocked by someone who didn't know what they were doing
But I'd be pleased to hear I'm wrong, because I don't like heating water for no reason either

For traditional solid fuel installations an unregulated cylinder was a must. With oil or gas you need some flow going back to the boiler which is regulated by its own thermostats which will switch it off.

If you fit the non electric valve you would also need to fit a bypass which will divert the flow to the return when there are no devices requesting heat. Another way of doing it is to fit a rad/or towel rad with both caps non adjustable.

With a three channel (two space and one water) programmer the boiler will switch off when the zone valve closes on the cylinder (and the other zones are not requesting heat) so there is no need for the bypass but it is a good safety feature in case one of your zone valves malfunction.

PS I've seen normal wheel valves been used as bypasses. They are just left slightly open to keep the flow going

stiofanD

_Brian_ wrote:

Theres absolutely no need for a motorized valve for hot water temperature control ,it's very expensive to do it that way.

The mechanical one by myson ,has a stat that goes against the cylinder and the heat acts to charge the valve to close. This means the only power you need to run the boiler is the pump ,gas valve ,fan.

Hi Brian, I'm also looking to install a valve to control flow to my hot water cylinder but I've not come across this mechanical one before. Sounds like just the job. I don't suppose you have a link to mysons web site which describes it or gives a product number for it. I presume I'd be able to get it in Heatmerchants or some place like that ?

10-10-20

Here it is:
http://www.myson.ie/pages/satcv.htm

311

There grand yokes ,just keep it about a third way up from the bottom of the cylinder.

If I don't reply to threads it's because I'm at work ,looks like I'm not the only plumber here anyways

lastbuilders

Thanks for the info guys. I will ask my plumber to install one of the Myson valves. He has to call to get his final payment so I can suggest "Oh, just one more thing" as Columbo would say.

Lastbuilders