Your wealth of knowledge re water pressure reducers

Haven't heard of that been an issue before but if it is couldn't you fit say a ball valve connection to the inlet where the hose connects up to the hot water system so that if the pressure is extreme you could turn it back a bit to the required pressure. Would probably cost all of $20 more if you went a stainless one. I would imagine you would have to be careful as to not reduce it to much and stop water flow. (I would think they have a safety feature to cut it out if this did happen) Regards Steve M

Gday Bunny.
Just a thought but how would the pressure reducers you buy for garden reticulation work? These are basically standard hose fitting in, larger barrel in the centre and back to the hose end again.
Cheers
Col

Bunny

How much of that $170 was for a pressure limiting valve, and how much for the labour to fit it?

Last time I looked, a PLV was about $40 - so maybe $140 or 2 hours to install. Seems a bit rich. Ring a local plumber and see if he could supply and fit one.

Max

Make sure you don't get pressure and flow mixed up. Flow is quantity of water in l/sec. past a point. Pressure is the force exerted on the inside surface area of the pipe, hotwater system tank etc that contains the water.
Spending the money on a balancing valve (about right at $170) makes good sense. Some ring mains in caravan parks can sit at 100psi if there is no load (drain) on them. If you get the ring main at say 50mm that is quite some considerable water hammering into your van. Turning a tap to reduce the flow will not reduce the pressure as the pressure will eventually build up to the mains pressure on the caravan side of the tap. What you will get is a huge burst of water followed by a trickle as the pressure dies off. It will then deliver water at the flow that the tap is set at.

To prove this get a gun thingy on the end of your garden hose (yes I realise these things may be foreign objects in some areas)
and only half open the tap. Then squeeze the trigger. Big water first then back to a moderate flow. It is the constant pressure that causes the problem no so much the flow. Where you might run into problems with small gas hot water systems is the flow is too great to allow the water to heat properly. The shower will have great 'pressure' (really flow) but the water will be cold because it has not remained in the heat exchanger long enough to get hot.

Spend the bucks and try to get an adjustable one if you can and stick a pressure guage on the van side of it to keep an eye on it. Your HW manufacturer should have listed a max pressure (in KPA or PSI) and flow (in litres per second) that the unit can take. Working out flow is easy. See how many seconds it takes to fill a 10lt bucket and do the maths.

Most of this info comes from bitter experience and years designing closed loop chilled water systems.

I am sure there will be other opinions and those that will question my logic but I urge the doubting thomases to try the hose experiment for themselves.

Better to be safe than wet I always think.

Craig

Well being a plumber i can buy the pressure limiting valve for under $50 and install it in around 15 minutes or less.The hws in your van should show inlet pressure and just buy the appropriate valve to protect the appliance.
Cheers Mark

Bunny,

Have a look at Camec's website, they have a variety of plastic pressure reducers for around $50.00. I have a brass one that fits onto the tap, but carry a plastic one as a spare (in case the brass one is stolen; sprayed it olive green to make it less obvious)

According to the instructions that came with my Attwood heater, the water supply should not exceed 450kPa or 65 PSI.

Mine clogged up and virtually stopped flow, I managed to get a new one for around $45.00 and did the re-install myself. Dead easy. The old one ended up being full of dirt from a wasp building a nest.
I now have a push on cover over the water in let to stop it happening again.

Pooley

Hi there. Went throught the same exercise last year. a domestic HWS type metal body pressure limiting valve was worth more than the caravan, but an irrigation grade plastic body pressure reducing valve was quite cheap, (both priced at my local Mitre 10). Easy to fit. Probably never know if it had to do its job, but worth the cost at around $30.

Don't stress.... These are already fitted to Coromal vans... A smallish brass cylinder in the line just after the water inlet. It's to protect the plastic pipe as well as the HWS etc...Will have the pressure stamped on it.