Calorifier Pressure Relief Valve drain - any bright ideas?

[alt]

My old calorifier didn't have a PRV, but my new one does... and it works! It has spat about 2 litres of water over the past month into the bilge, so need to sort out a drain.

Does anyone have any bright ideas as to where to plumb it to? I'm lucky that there is a plastic section under the seating in the cockpit which I can easily drill into and put the exit of the drain pipe there (won't be seen), therefore it will just drain into the cockpit. I can't think of anything else? I don't want to drill gelcoat / fit a skin (to chuck it out over the side)

 

[longjohnsilver]

How about an expansion tank?

 

[Lon nan Gruagach]

There will be a good pressure behind it, you might go up and over to any exisitng drain.

 

[aquatom]

not a good idea to direct it into the cockpit. If engine overheats it can cause the relief valve to blow off spraying very very hot water / steam into the cockpit where people may be!

 

[alt]

I'm going to bite the bullet and T into an existing drain... just involves more labour, but the safer option (as mentioned above)

Thanks folks

 

[Robin]

ours used to drain to the bilge along with the fridge/freezer box drain and the aircon drains, but we now have them all go to a shower sump box with a built in automatic pump that goes to a tee in the aircon cooling water overboard pipework, I like dusty bilges!

 

[alt]

ours used to drain to the bilge along with the fridge/freezer box drain and the aircon drains, but we now have them all go to a shower sump box with a built in automatic pump that goes to a tee in the aircon cooling water overboard pipework, I like dusty bilges!

I agree, bilges should not be for draining things into! I got a shock when I saw the bit of water in the bilge the other day, but thankfully realised soon it was the PRV... easy to sort that one out.

Mad that our old one didn't have one, though

 

[Robin]

I agree, bilges should not be for draining things into! I got a shock when I saw the bit of water in the bilge the other day, but thankfully realised soon it was the PRV... easy to sort that one out.

Mad that our old one didn't have one, though

nor did ours we had to buy one, the regular shower sump has a manually switched remote mounted pump that we couldn't conveniently use. The shower sump/pump we fitted was a stock item in West Marine USA, for around $130 and is about an 8 inch square box with multiple inlets http://www.westmarine.com/buy/west-marine--multiple-port-shower-sump--15919749

 

[TrueBlue]

Not a lot of point in just draining the fluid 'somewhere' - as I discovered last year. (ended up with the contents of my freshwater tank in the bilge....)
If it's regular then either the pump pressure is greater that the PRV relief or the valve itself or it needs to be 'cleaned'. There will always be a small dribble, so I discharge it into a bottle in the bilge. If that fills up regularly - I find out what caused it. (The bottle overflows and runs into the bilge.

Just another thing to check 'regularly'

All FWIW

 

[P4Paul]

My old calorifier didn't have a PRV, but my new one does... and it works! It has spat about 2 litres of water over the past month into the bilge, so need to sort out a drain.

Does anyone have any bright ideas as to where to plumb it to? I'm lucky that there is a plastic section under the seating in the cockpit which I can easily drill into and put the exit of the drain pipe there (won't be seen), therefore it will just drain into the cockpit. I can't think of anything else? I don't want to drill gelcoat / fit a skin (to chuck it out over the side)

I plumbed ours into one of the deck drains which ran next to the calorofier. The outer diameter of the calorifier PRV pipe was the same size as the inner diameter of the drain so it was a straight forward job using a t-piece and a few odds and sods I had kicking about in the shed after building the extension. I put an air break (anti siphon) in the loop of pipe and a check valve to prevent deck water getting anywhere near the domestic supply.

Been like it for three years, no problems and lovely dry bilges!

 

[Momac]

I have never noticed any water escape from the pressure relief valve in two boats with the same thing and over 7 years.
If the valve is letting water escape does this not indicate a fault? Is the immersion heater set too hot or the new valve faulty?

 

[alt]

I have never noticed any water escape from the pressure relief valve in two boats with the same thing and over 7 years.
If the valve is letting water escape does this not indicate a fault? Is the immersion heater set too hot or the new valve faulty?

Actually, that's a good point, the immersion element may be set too high. I'll set it lower this weekend and see if it sorts the issue, before taking to installing new piping

 

[aquapower]

Actually, that's a good point, the immersion element may be set too high. I'll set it lower this weekend and see if it sorts the issue, before taking to installing new piping

If you haven't got expansion vessel then each time you heat the tank it will push some water out the relief valve as it expands, a correctly installed water system will not push water out of relief valve every time you heat the tank.

 

[alt]

If you haven't got expansion vessel then each time you heat the tank it will push some water out the relief valve as it expands, a correctly installed water system will not push water out of relief valve every time you heat the tank.

It didn't push out water every time, as I only noticed water in the bilge last week (calorifier been in the boat over a month). There was no pressure relief valve on the previous calorifier, so surely there is an expansion tank? When you say expansion tank, is that the same as an accumulator tank? (I'm guessing not as that is on the cold feed?)

 

[P4Paul]

I have never noticed any water escape from the pressure relief valve in two boats with the same thing and over 7 years.
If the valve is letting water escape does this not indicate a fault? Is the immersion heater set too hot or the new valve faulty?

The PRV on our calorifier lets go when being heated by the engine running rather than when heated when berthed by the immersion coil.

 

[Robin]

The PRV on our calorifier lets go when being heated by the engine running rather than when heated when berthed by the immersion coil.

+1 it gets much hotter from the engine running than from the immersion, usually.

 

[longjohnsilver]

It didn't push out water every time, as I only noticed water in the bilge last week (calorifier been in the boat over a month). There was no pressure relief valve on the previous calorifier, so surely there is an expansion tank? When you say expansion tank, is that the same as an accumulator tank? (I'm guessing not as that is on the cold feed?)

You have a surecal, I also fitted one shortly after your thread, and whilst i haven't fitted an expansion tank I'm pretty sure that the instructions recommend fitting one - hence my suggestion in post 2.

Maybe worth looking at the manual or speaking to surecal?

 

[aquapower]

It didn't push out water every time, as I only noticed water in the bilge last week (calorifier been in the boat over a month). There was no pressure relief valve on the previous calorifier, so surely there is an expansion tank? When you say expansion tank, is that the same as an accumulator tank? (I'm guessing not as that is on the cold feed?)

This explains both, there's a non return valve in the cold inlet, the only escape for expansion when tank gets hot without expansion tank fitted is through relief valve.


http://www.surecal.co.uk/Product/ExpansionTanks.aspx

http://www.surecal.co.uk/Product/AccumulatorTanks.aspx

 

[beebok]

We had this problem on our old boat, it was the expansion tank bladder that was beginning to perish so air escaping and then the pump continued to work overtime and caused the PRV to release pressure on the calorifier.
Replaced the expansion tank all ok.
On our current boat same problem but all we needed to do is was to turn the valve,its spring loaded,a couple of times and all ok.

 

[alt]

Thanks for the info folks. It seems the easiest solution here is to just run a drain for the PRV