Cutting Hole in Cold Water Cistern

[gileto]

Hi

Am connecting the pipework from my power shower to my galvanised steel cold water cistern in the loft above.

The new hole has to be (at least an inch) below the existing outlet to the hot water tank - but this hole is already very low.

My questions are:

1. What's the best way of cutting the hole - ie with a holesaw I presume, but any special type?

2. Any problems foreseen in cutting the new hole in the bottom of the tank as opposed to through the lowest point on one of the tank walls?

Thanks for any info.

Paul

 

[breezer]

i would use a hole saw. but make sure its got enough room on inside for nut to fit

 

[gigz]

If you do go through the bottom (ooo err) make sure you've got an inline filter fitted and clean the tank out whilst its empty

 

[Watchmaker]

If the galvanised tank is old, it should be closely inspected to see if there is any rusting in the bottom. This will indicate if the galvanizing is failing and, if it is, it might be time to replace it with a modern non rusting composition type tank If you do not have access to a holesaw, the maximum diameter of the required hole can be marked, and a ring of small holes drilled inside this mark. The hole can then be carefully filed to suit the threaded pipe adaptor. However, a holesaw or drilling/filing, will expose an ungalvanised edge which could accelerate future corrosion.

 

[bster]

replace it with a nice'n' new plastic jobby complete with snappy lids and other good stuff

 

[Goodman]

And do not forget the overflow connections at the top of the tank and service valve for the main feed

 

[TicklyT]

Can you fit a new flange an inch or so higher, and transpose the hot and cold feeds, so the cold outlet is below the hot outlet?

Thoroughly clean out any metal filings after cutting the hole (a magnet is useful), as any left in the tank will cause the galvanising to pinhole through electrolytic corrosion.

 

[ChrisR]

Throw it away and put a plastic tank in, to current regs, with a nice fast quiet filling float valve like a Fluidmaster.
You'll have cleaner water, proper insulation, and be free of the hassle of dealing with 50 gallons of water coming through your ceiling when it rusts through.

 

[Nige F]

Hi

1. What's the best way of cutting the hole - ie with a holesaw I presume, but any special type?

2. Any problems foreseen in cutting the new hole in the bottom of the tank as opposed to through the lowest point on one of the tank walls?

Thanks for any info.

Paul

1..Starrett 2....that`s recommended now ....but with the proviso that you dont store "girlie mags" where they can fall into the cistern and lay over the outlet in the bottom and stop the flow ........yes it happened @ a flat in Surbiton.....laughed so much I nearly didn`t charge them