as a conventional above ground swimming pool 15 ft dia heater (electro) is just
a heating chamber, cold water in one side passing over internal heating element
and warm water out coupled into the filter system with a temperature control
and safety cut out is there any reason why a shower unit could be used instead.
They have the same features and reqirements and the filter pump delivers the
necessary flow rate. They come in 3kw, 4.5kw for this size pool. Coupling the
shower unit to the filter pump water circulation is not a problem nor is the
electrical supply in this instance. The only difference that I can see is the
price (£300+ for the pool heater as opposed to anything from £50 to £100 for a
shower unit that meets the flow rate and KW requirements) Is this possible do
you think or an impending DIY disaster! I would be most gratefull for any
guidance offered before I take the plunge, so to speak. My plumbing and wiring
skills are now more than sufficient to tackle this so that is not a problem.
On 22 Jul 2003 11:22:34 GMT, Smithwood456789 wrote:
Several things come immediately to mind. What size is the existing filter
pump pipe-work? Is the shower unit pipe-work of similar size or smaller?
Will connecting the shower unit reduce the flow-rate appreciably? Will the
shower unit withstand the chlorine levels withing the pool? If you use slow
release tablets in the skimmer, the chlorine levels will be appreciably
higher than the body of the pool water. Also the shower unit *must* be
wired so that it can only come on when the pump is running. It is also
prudent to operate the pump for at least 30 mins before and after the
heater unit, to minise the risk of scale build up.
I am assuming that you have all supplies to the pool electrics fed by a
30mA RCD device.
On Tue, 22 Jul 2003 13:42:09 +0100, Christian McArdle wrote:
Hmm, pool heaters are essentially un-vented flow boilers (albeit with an
excess pressure safety valve). It's the passage of water through the boiler
that keeps it operating safely. They *must* be wired so that they only work
when the filter pump is on. I think you'd need to get some sort of cylinder
that was little bigger than the bore of the (usual) inch and half diameter
~~~~ Immersion heater
in vented tank
The thermostat would prevent boiling in the normal way if
the pump failed.
The first flow restrictor could be set so the pressure in the tank during
pump operation was not sufficient to blow water out the vent.
The whole heater section is an "add-on" that can be isolated for repair.
(anti-spam is as easy as 1-2-3 - not)
Reminds me of the tricks people used to get up to in order to warm the
water in our church baptistry. My earliest memory is of a device about
4ft tall (the electrical connection box was just out of the water) which
stood on the baptistry floor like a tubular metal foot. The church we
borrowed it from had 15A round pin plugs, and we had to put a 13A square
pin on for it to work - the plug used to get very hot but the fuse never
Then someone had a bright idea. They bought two galvanised metal buckets
and fitted a standard immersion heater in each - the idea being to
float the buckets on the water. Even at 12 I could see that that was a
When I was baptised the water was more-or-less cold straight from the
tap (via a hose) though we did fill it up the previous day and leave the
feeble church heating on. When my sister was baptised, all three of the
aforementioned heating devices were used and it was like a sauna.
Several times I, personally, spent hours in the church boiling and
re-boiling the tea urn and kettles to try to take the edge off the cold.
Nowadays, of course, it's been plumbed up with a cold tap and hot water
through the hall's combi boiler. It doesn't exactly fill quickly (I'd
say it is about 8ft by 5ft by 4ft deep, ignoring steps) but now that
it's been GRP lined it fills slightly more quickly than it used to. Just
before the decision was made to line it, it would lose 6" in about an
Martin Angove (it's Cornish for "Smith") - ARM/Digital SA110 RPC
See the Aber Valley -- http://www.tridwr.demon.co.uk/abervalley.html
"Martin Angove" wrote
| Reminds me of the tricks people used to get up to in order to warm the
| water in our church baptistry.
| Then someone had a bright idea. They bought two galvanised metal buckets
| and fitted a standard immersion heater in each - the idea being to
| float the buckets on the water. Even at 12 I could see that that was a
| bit dodgy.
You don't need an RCD if you put your trust in Jesus!
Whilst I realise that a commercial heater is likely to be unvented, I think
a DIY solution would be much safer with a conventional vent. Then you don't
have to worry about explosions so much. As long as the vent is higher than
the head produced by the pump plus a bit to spare, it shouldn't pump over.
Relying on the pump to keep working or a flow switch to work doesn't seem as
safe as a 2 metre length of pipe, which has fewer failure modes. Obviously,
the heater would be interlocked with the pump supply anyway, so there are at
least 2 safety devices.
How do you come to that conclusion? Do you have any figures to substantiate
I use an 18kw flow boiler with my pool, (10,000 gallons) and that brings
it to a temperature of about 27 or 28C without any problem, at an annual
cost of about £300. With solar gain through the buble cover, the pool has
been at about 32 or 33C for the last five or six weeks.
That presupposes you have room for the panels. In my case I don't.
Off peak electricity 3.25 p per kWh
Oil is about 1.4 p per kWh
Oil boilers are less efficient than heating by electricity but even so
you can already appreciate the difference.
I have an oil boiler too, I just prefer to use 'green' energy where
practical - and save some cash to boot.
Failing that, oil is best in terms of both cost and probably
green-ness too because of the efficiency loss associated with burning
coal in a power station, making electricity, transporting it through
substations etc. and converting it to heat at the other end.
It is in fact possible to heat solar without panels. Nearly vertical
reflective sheets can be used to direct sun straight into the pool.
Its cheap and simple, and when you use the pool you can draw the
reflective curtains back so you dont get over-sunned.
There is usually room for these, tho certainly not always.
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