Central heating query

[scottpetrie]

hi
Im about to refit my bathroom and need to switch off water supply as theres no isolation valves fitted. Im also going to be installing a towel warmer in place of radiator. My central heating is a boiler in kitchen, tank in airing cupboard with expansion vessel above it. There is one header tank in the loft. Is this for the water only or does this supply water to the radiators? Reason Im asking is Im wondering how to add inhibitor to the heating once I put in new towel warmer. Dont want to add it to header tank if this is also bathroom water for showering/brushing teeth in. Also need to know what valves to shut in to shut off water supply without emptying the header tank

 

[stem]

As you have an expansion vessel near the hot water cylinder, It would appear that you may have an unvented hot water cylinder which would be supplied from the mains water supply and not a storage tank, so the tank may well feed the boiler and radiators. This tank is usually very small about 4 gallon capacity.

Of course it could be the other way around and the expansion vessel is for the boiler and the tank feeds the hot water cylinder. However, in this case the tank would be much larger about 30 gallons or more.

If you turn off the cold main water supply. Does the hot water supply from the taps stop also? If not and it continues to run for a long period of time then it will be being fed by a tank.

Regardless of that the easiest way to add inhibitor is usually by dosing it via a tower rail after isolating it, removing the plug from the top and siphoning out a volume of water equal to the inhibitor that you want to put in.

Before you proceed though, just be aware that a towel rail will only emit about one third of the heat that a single radiator of the same size does. And that's when it's uncovered. It will reduce down further to almost nothing when it is covered with fluffy insulating towels. So, unless your bathroom is warm enough now without the radiator being on, I would leave the existing radiator in situ and install the towel rail separately elsewhere, otherwise you may find that it is cold in the bathroom in the winter.

 

[scottpetrie]

There is only one, quite large tank in my loft. I havent tried shutting off any valves yet, still tryi g to make sure Ive located the right ones. As Im putting in a new shower, does that mean it will be hravity fed? My current one has bery poor pressure, but Im just hoping its because its very old and is blocked up

 

[stem]

There is only one, quite large tank in my loft. I havent tried shutting off any valves yet, still tryi g to make sure Ive located the right ones.

The valve I referred to is the main isolation valve on your incoming cold water supply. The one you would normally turn off in an emergency. You must know where that is, right?

As Im putting in a new shower, does that mean it will be hravity fed?

That will depend upon your existing hot water system. If the existing hot water system is gravity fed it will be, if it's not gravity fed then it won't be.

 

[heatservice]

Your shower pressure will be determined by the distance the CW tank is above the shower head, both your supplies to HW cylinder and shower CW should be fed from the same tank, the cold tapping should be taken from a lower point than the one supplying you cylinder, so should the tank fail to refill the cold water would still flow after the hot failed eliminating any risk of scalding.

 

[scottpetrie]

Yes I know where the main supply valve is. Just trying to locate any others so I dont empty the tank when I isolate the water. Could I tee off the cold bath tap and run a pipe up to the new shower, meaning I would have mains pressure to the shower. I live in a bungalow and the tank is directly above the shower, so I imagine not giving much pressure.

 

[stem]

Yes I know where the main supply valve is.

Ah OK, sorry. When you said

I havent tried shutting off any valves yet, still tryi g to make sure Ive located the right ones.

I thought you were responding to my suggestion to determine if your hot water system was gravity or not.

If you turn off the cold main water supply. Does the hot water supply from the taps stop also? If not and it continues to run for a long period of time then it will be being fed by a tank.

 

[heatservice]

Yes I know where the main supply valve is. Just trying to locate any others so I dont empty the tank when I isolate the water. Could I tee off the cold bath tap and run a pipe up to the new shower, meaning I would have mains pressure to the shower. I live in a bungalow and the tank is directly above the shower, so I imagine not giving much pressure.

Have you considered having an electric shower, the approved way is to have hot & cold at the same head pressure, to increase the pressure you would need to raise the storage tank (if possible) or incorporate a pump, neither option would be cheap, you cant just go mixing high & low pressures with a shower mixer.