Water pump for hot water unit
Submitted: Saturday, May 01, 2010 at 22:30
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SmokeyD
Hi folks,
I have a question re my newly aquired Mercury instantanious hot
water unit. It is rated at 6 litres per minute, and I have to choose the 12 volt
water pump to go with it. Considering the
water heater's rating, would it make any difference what PSI/Litre per minute pump I chose? By that I mean, would I get a stronger flow out of the shower rose/sink tap if I chose say a 60 PSI/17 litre per minute unit over a lower output model?
Reply By: Member - mazcan - Saturday, May 01, 2010 at 23:12
Saturday, May 01, 2010 at 23:12
hi smokeyd
yes it would but you'd also use twice as much
water
but you'd be asking for trouble
to put a pump on your instant hot
water system thats rated twice what the unit flow rate is would in my honest opinion probably blow it apart or put unnecessary strain internally and cause premature failure
shurflow make a small pump about 5.5l/per min which would ideal
cheers
AnswerID:
415054
Follow Up By: SmokeyD - Saturday, May 01, 2010 at 23:37
Saturday, May 01, 2010 at 23:37
Hi mazcan,
Oh, ok - understand your point. Just worried about pressure under the shower, don't want to have a pathetic dribble at the rose considering the height it has to pump (ie head height).
Cheers.
FollowupID:
685236
Follow Up By: Crackles - Sunday, May 02, 2010 at 00:29
Sunday, May 02, 2010 at 00:29
My understanding is the Mercury unit can be connected into a house on mains pressure so doubt any 12 volt pump would be a problem.
At one of the 4x4 shows they were running an 11L per min pump.
Cheers Craig...........
FollowupID:
685239
Follow Up By: Member - mazcan - Sunday, May 02, 2010 at 15:35
Sunday, May 02, 2010 at 15:35
hi smokey d
your response of
ok- ok i understand your point
is not what i was expecting as i was simply giving my honest answer to your question
you never said the unit in question was capable of mains
water pressure so i was giving my honest opinion based on facts presented
the pump i recommended is the same as i used on a farm spraying unit
and it had enough pressure to squirt
water 3mtrs accross the ground at weeds out of a spraygun nozzle on the end of a 10mtr hose
so i hope this will alay your fears of not having enough pressure at the shower head
these pumps last for a very long time i bought it in'84 and now use it on my present camper trailer which i connect to a free standing shower and primus
water heater hope this has helped you in some way
have a good day from here on in
cheers
FollowupID:
685287
Follow Up By: SmokeyD - Sunday, May 02, 2010 at 23:50
Sunday, May 02, 2010 at 23:50
Hi Mazcan,
Um - if you look at my first reply to you I actually said "Oh, ok - understand your point." Nothing terse meant in that reply at all - and I didn't know that the units could be hooked up to mains pressure, as I bought what I thought was a hot
water unit for
camping, as it was advertised. So I appreciate your reply as I do all who give their time for others a little less knowledgeable.
Thanks again.
FollowupID:
685341
Reply By: Crackles - Saturday, May 01, 2010 at 23:42
Saturday, May 01, 2010 at 23:42
Pump size will not greatly increase the flow out of the unit as it has it's own regulator (
Water dial on the right). A higher flow (17L) would be pointless as it would barely come out luke warm. The arbitrary 6 litre rating is for a 25 degree increase in
water temp so if the
water is cold to start with the flow may need to be as little as 3 litres per minute to get it hot enough for a shower.
Cheers Craig.......
AnswerID:
415057
Reply By: Ozhumvee - Sunday, May 02, 2010 at 09:33
Sunday, May 02, 2010 at 09:33
We've had one of those hot
water heaters working in shed for a few years now and even on mains pressure it can heat the
water far too hot for a shower if set incorrectly with gas versus
water flow.
So I wouldn't worry about any pump being too strong for it or pushing too much
water.
A bigger consideration is how much
water you can use in a short time when
camping.
I've tried it on very setting from a slow dribble on the garden hose to full pressure and it works
well with its rated capacity of about 6l/min. You can have a good shower with 3l/min but if flow drops below that the heater turns off.
I'd get a pump of about 5-6l/min as the best. You still need to turn
water off when sopaing up or you will quickly get through 20l+ in a 3 min shower.
AnswerID:
415079