Replacing copper HW tank.

[Steve Walker]

Pre-insulated is nice - except then the previous tank is in a cupboard that is big enough for the new tank, but not big enough to manouevre it in. I had to cut of half-a-dozen central heating pipes and remove valves and pump to get the tank in and then rejoin all the pipes.

Me too, but ours has failed in an odd way. I am asumming that the element has warped towards the stat tube. It works once and trips out the overheat trip. I have replaced the stat a couple of times and the problem remains. Of course the heater has siezed into the tank and will not come out.

At least I can reset it and use it once if we really need to.

SteveW

[tabbypurr]

Have you tried automatic transmission fluid? It's an awesome unsiezer Might be easier to just use a separate stat. Must be 13A rated.

NT

[Steve Walker]

I could use an external stat, but I'd also need to add an external overtemp trip. The other option is to cut a hole in the tank and add a new boss.

SteveW

[tabbypurr]

You only need to wire over one stat & replace it with external.

Another option is to run it on reduced voltage if you have a 1kVA 110v tran sformer. Wise to overrate it as it'll run for over an hour at a time.

NT

[The Natural Philosopher]

The thought of going bacl to header tanks and low pressure hot water just amuses me really.

[Chris Hogg]

I'll look forward to that now we've got it installed anyway.

[John Rumm]

If you already have a vented system that works well, a fast recovery cylinder, and have pumps installed for showers, then there is not much value to be had ripping and replacing it for the sake of it.

In my case the existing system did not work at all in some respects and was ill suited to the property. The only shower pump had died long ago. So it was a no brainer since I was changing the boiler anyway.

[tabbypurr]

Some vented systems work fine with slow recovery and no pump. As said there's only a reason to rework them when they don't work.

NT

[Andrew]

Mine is the houses original tank from 1976 and there is nothing wrong with it.

Is this a case of 'it aint broke so why fix it' ?, especially since you are only contemplating a like-for-like swap. If there is space and you have the possibility of some form of solar panel too (and are young enough to get any financial benefit) then a larger tank that has dual heating coils might be worthwhile upgrade, but do the maths.

Are your joists strong enough to support a much larger tank, something that people don't consider ?.

More information would help like :-

Age and size of property Number of people and age Number of bathrooms and distance from hot tank. Type of heating appliance.

[Andrew]

There are still a couple of near neighbours with their original (1976) baxi bermuda back boilers and 28mm gravity fed hot tanks. These must be the ones that were installed properly first time around and the owners have managed to defy BG with their standard advice about 'cannot get the parts'.

Both houses are centre terrace so less heat loss to worry about.

[Andrew]

How do you know your heating engineer (and I hope has was, and not just a plumber) didn't just specify the solution that gave him the highest markup ?.

For mains pressure tanks he needs an extra certificate that J Bloggs, overpriced-tap-washers-r-us doesn't have.

[Andrew]

If I replaced my bog standard tank with one of those, bearing in mind the appalling way the 1st floor joists were attached with joist hangers (4 or 5, 4 inch round nails half in and then bashed over), it might end up in the lounge.

There is already 20mm ceiling deflection where the tank is !!

[Andrew]

What happned to the thermostatic control that limits the temp at the tap to no more than ?50. Did this ever become a building regs requirement ?.

[Andrew]

Another neighbour who fell for the BG 'No parts' scam had their baxi bermuda replaced by a WB Junior ??12RI. Wife decided that they 'needed' a new tank with more insulation and the one used seemed to have about 4 inches of foam. It only just fitted through the airing cupboard door afaik.

They also had a fancy wireless stat that has been replaced three times. BG say it is their fault because they opted out of the £12 per month 'option' to allow BG to dial in and reset it remotely !. BG claim that this boiler won't work with a conventional room stat. This I think is pork-pies.

[John Rumm]

From the doc above:

Prevention of scalding

3.65 The hot water supply temperature to a bath should be limited to a maximum of 48°C by use of an in-line blending valve or other appropriate temperature control device, with a maximum temperature stop and a suitable arrangement of pipework.

and also:

Prevention of excessive temperatures

3.64 Where the operating temperature of domestic hot water in the storage vessel in a dwelling is capable of exceeding 80°C under normal operating conditions (a situation that may occur in vessels used as heat stores and those connected to solar heat collectors or solid fuel boilers that do not have intervening controls between the boiler and the vessel containing the hot water) the outlet from the storage vessel should be fitted with a device, such as an in-line hot water supply tempering valve in accordance with BS EN 15092:2008 Building Valves. In-line hot water tempering valves, to ensure that the temperature supplied to the domestic hot water distribution system does not exceed 60°C.

[Chris J Dixon]

My similar foamed tank is in the integral garage and I wondered if there was any point in adding any extra insulation? There isn't a lot of clearance, but I suppose I might drape something over the top similar to the old jackets.

Chris

[tabbypurr]

If it's in a cupboard the space can be packed with junk insulation, avoiding any flex feeding he immersion. If no cupboard it's easy to construct a flimsy outer wrap that can be stuffed with insulating junk, or apply roll insulation & tie.

NT

[Cynic]

There are as you suggest "safety features but unless correctly installed and commissioned the risk remains. Too many bodge artists out there!

[newshound]

+1

When I went from a combi (I already had a separate vented immersion tank running a shower) to a system boiler, I just put in an ordinary modern cylinder with heating coil, not a special fast recovery one. Plus an ST pump for DHW, and a double ST for the shower.

Much less complication and no problem with recovery times.

[John Rumm]

I would have thought if you need to replace a cylinder and install two pumps, I am not sure that really qualifies under the "less complexity" category!

If its a relatively recent one, then it will be fairly quick recovery anyway. How the system is zoned will also have a big influence on recovery times.