Calorifier and expansion tanks.. ?

captainslarty

captainslarty

N/A
Joined
12 Aug 2007
Messages
2,008
Location
Currently La Coruna Spain
Visit site
this was mentioned a few days ago in a thread... I am interested to know the general setup...
Please can anyone post a diagram of such a system including valves etc...
Or, describe it.. but a pic is worth 1kwords lol

Thankyou
 
The expansion tank is fitted after the calorier so that as the water heats up and the volume increases the pressure increase is miminised. There are no valves. Its just a tank with air in to cushion the increase in water volume. Air being compressible and liquids are not (much).
 
Recomendation is that it should be about 10% of the hot water tank capacity. If you don't fit one every time the tank heats up water will blow out of the pressure relese valve, not only wasts water but usualy finishes up in the bilge. Fits on a 'T' connection anywhere on the hot water supply line
 
Before I took it out, the system I had was;
calorifier on the engine pumping water through a pipe which ran through the hot water cylinder in a coil before returning to the calorifier.
The heat of the water in the pipe transferred by conduction to the water in the cylinder.

From the cold water storage tank a pipe ran to a pressure pump and from there it branched to the cold taps on one side and the cylinder on the other. The pump would operate on demand from a pressure switch located in its body. Low pressure on, high pressure off. Therefore the system would always be under a certain pressure until a tap was turned on when the pressure would drop and the pump switch on.
Because of the lack of size of the pipework and the pressure in the system it didn't take more than a few seconds before the pump would switch on and it would achieve max. pressure fairly quickly and so it would be 'cycling', which is not the best way for the pump to operate.
To get round this the designers fitted an expansion tank after the pump but before the 'T' and this gave the system a far larger capacity so cutting down on the cycling and improving the life of the pump and subsequent noise reduction (noticeable at night)

Sorry, not very well put, but it was a good night last night, and I am sure someone will help out if bits are wrong.
 
I have an expansion tank immediately after the pressurising pump, cold water then goes about 2 metres to a Y-valve, from there either to the calorifier or to cold water taps. Route for the hot system is about 3 metres from the Y-valve. I have no other expansion tank and the calorifier has never once leaked water into the bilge or anywhere else. This applies to two calorifiers that have been in this location.
 
I'm just replacing a system with a pressurising pump feeding cold water system & calorifier heated by engine water (with a similar setup in different location) - no expansion tank anywhere

Never noticed the old system leaking into the bilges.

Don't really understand why it should - I can understand the need for a pressure relief valve - but water only expands about 4% from 0 to boiling - I would have thought that normally this could be absorbed by just increasing the overall pressure in the pipes / tank a little ?

Lots of diagrams here:
http://www.tb-training.co.uk/17Bdomwat.html
 
Thanks for the replies all.
We have the standard setup here on Ruddles. Tank to pump - accumulator on output of pump, y to cold tap and hot tank (Calorifier), output of hot tank to hot tap.
The only 'problem' we are getting is sometimes the hot leaks back ito the cold system, you turn on the cold tap and get hot water for a few seconds.. not good...
this is with the 240v immersion type heater on 24/7 whilst in marina.
there IS a one way valve in the cold feed into the calorifier. but this seems to be being bypassed, I have replaced it and still have the problem.
There is also a rather complex looking valve arrangement on the calorifier with an adjustable knob.. I must confess to having no idea what that is for.

Joe.
 
2006364833069666639_rs.jpg


Old piccy (before we removed the old drains) but hopefully you can see the valve.
 
[ QUOTE ]
There is also a rather complex looking valve arrangement on the calorifier with an adjustable knob.. I must confess to having no idea what that is for.

[/ QUOTE ]It's a thermostatic mixer valve. With modern engines, the water in the calorifier can get very hot - much hotter than is comfortable for use. The thermostatic valve automatically mixes cold water in with the hot water leaving the calorifier so as to lower the temperature to a more usable level. The added benefit of this is that the hot water capacity can last longer. You can adjust the thermostatic valve to suit your needs. If the hot water in the tank is cooler than the valve's setting, obviously no cold water is added.
 
Thanks PVB.. just got off me ass and googled surecal and found this...

surecal fitting instructions

Doh !

my excuse for bone idleness is that the weather hear is horrendous at the mo, peeing down and gales, and the calorifier is under the cockpit floor !! didnt want to get soaking finding out the make !.. then I looked at the old piccies and found one with the calorifier on, AND the make written on it...

and yes, seems they recommend a seperate hot expansion vessel...

Joe.
 
I've got a valve like that on the new tank I am fitting - its the pressure relief valve - and T for hot water out and overflow.

All the "knob" does is allow you to test that the pressure relief valve hasn't stuck (according to the blurb this should be checked regularly of course!)

Actually just seen they (C-Warm) say that an accumulator should be fitted to avoid slight leak (dribble) via the pressure release valve - which over time may cause the vale to jam
 
[ QUOTE ]
I've got a valve like that on the new tank I am fitting - its the pressure relief valve - and T for hot water out and overflow.

All the "knob" does is allow you to test that the pressure relief valve hasn't stuck (according to the blurb this should be checked regularly of course!)

Actually just seen they (C-Warm) say that an accumulator should be fitted to avoid slight leak (dribble) via the pressure release valve - which over time may cause the vale to jam

[/ QUOTE ]Yours may be a pressure relief valve, but his is a thermostatic mixer valve! C-Warm calorifiers, like yours, are one of the few makes which don't have a thermostatic mixer valve as standard, although C-Warm sell one as an accessory. It would be worth your while to fit one to your new calorifier.
 
Excellent Danny thanks
Am I right in presuming any type of accumulator would work ?.. a normal jabsco type for instance.. or does it have to be a 'high temp' model for hot water.. havent looked at the prices yet but the coldwater ones are cheap.. and I am back in the uk in 2weeks.

Oh, Danny, what type of one way valve did you fit ?
 
Quote,
I've got a valve like that on the new tank I am fitting - its the pressure relief valve
......................................................................................
Pressure relief valves are usually fitted lower down the tank, and generally have a red handle for manual testing.
 
Thanks - will look into that - presumably that stops me getting 90 degree hot water coming out (and yes it is fitted lower on the tank)

Old tank was setup on raw water colled engine - so less of an issue I guess. New Beta gets water a fairr bit warmer so as you say may be worth looking at
 
You must log in or register to reply here.

Share this page

Top