Bit of a prob' with calorifier

[ROBDEN]

Hello….again.

 

My hot water is nowhere near as hot as it used to be.

For a while now I’ve suspected that there’s an air lock in the system.

 

I’ve tried the usual things to get rid of it, like shouting, screaming, swearing at it and even hitting it with a tree branch but nothing worked.

Tried running with the hoses off and pouring water in the header tank but still no change.

 

Yesterday I thought I’ll try again.

 

When I removed the calorifier - return to engine - hose, no water ran out. I could see water in the hose but it wouldn’t run out.

So I removed the inlet hose, still it didn’t run out.

The only way I could shift it was to blow down the inlet ( quite hard ) until it moved but if I stopped blowing the water stopped coming out.

 

Now I’m thinking that there’s a partial blockage somewhere in the system.

Is it alright to backflush a calorifier with mains pressure the next time I’m at a water point?

Or, do you think the boats Jabsco water pump will give enough pressure?

 

Or, any other ideas?

 

Many thanks for any help/advice.

 

Rob….

[Black Country Lee]

Back flushing will be fine, best to do it 3 or 4 times in opposing directions to completely clear any 'crud' out.

 

Lee.

[Neil Smith]

How old is your system? has it had regular antifreeze changes or kept topped with a corrosion inhibiter? If so you should not have crud in the system, If not you might have a lime scale build up and all the flushing in the world wont budge it, then you have 3 options either take it out block one end and pour kettle descaler in until full and leave over night or a strong solution of caustic soda about £1 so cheapest, Option 2 if you don't want to remove tank make up a filler pipe on the highest fitting and fill that way.

Option 3 get a plumber to do a power flush, expensive but no work on your part.

 

Neil

[ditchcrawler]

Have you had a Jabsco pump impeller failure in the past ?

[ROBDEN]

Have you had a Jabsco pump impeller failure in the past ?

 

No but how’s that relevant?

 

Unless you thought I meant the pump was on the engine.

My fault, I should have said fresh water house pump.

 

Rob….

[blackrose]

I assume you've tried manually opening the spring-loaded pressure release valve on the calorifier as a starter? If it's stuck closed then perhaps that's building up pressure and adversely affecting things?

[ditchcrawler]

 

No but how’s that relevant?

 

Unless you thought I meant the pump was on the engine.

My fault, I should have said fresh water house pump.

 

Rob….

I assumed you were having problems getting water round the heating coils in your calorifer to heat the water. these would be fed from your engine, backboiler on fire or ebbispatcher type heater and not pumped round by your domestic pump. In the case of the engine coil it would be by the engine water pump. If it were a jabsco type a broken piece of impeller could be blocking the coil.

Now I don't have a clue where you are trying to get the water through so will leave it to others to advise.

[ROBDEN]

Back flushing will be fine, best to do it 3 or 4 times in opposing directions to completely clear any 'crud' out.

 

Lee.

Thanks for that Lee.

 

Rob....

 

I assume you've tried manually opening the spring-loaded pressure release valve on the calorifier as a starter? If it's stuck closed then perhaps that's building up pressure and adversely affecting things?

 

PSV is ok thanks.

 

Rob....

[ROBDEN]

I assumed you were having problems getting water round the heating coils in your calorifer to heat the water. these would be fed from your engine, backboiler on fire or ebbispatcher type heater and not pumped round by your domestic pump. In the case of the engine coil it would be by the engine water pump. If it were a jabsco type a broken piece of impeller could be blocking the coil.

Now I don't have a clue where you are trying to get the water through so will leave it to others to advise.

 

Your assumption is correct.

Water is heated (not very well) via engine pump.

 

What I meant was, I have a spare Jabsco fresh water pump and was wondering, if I set it up, would there be enough pressure to back flush the calorifier?

 

Rob....

[ditchcrawler]

 

Your assumption is correct.

Water is heated (not very well) via engine pump.

 

What I meant was, I have a spare Jabsco fresh water pump and was wondering, if I set it up, would there be enough pressure to back flush the calorifier?

 

Rob....

OK, is the water leaving the engine for the calorifier hot

[ROBDEN]

OK, is the water leaving the engine for the calorifier hot

 

Yes. Engine to calorifier hose very hot.

Return hose quite warm.

Domestic (hot) water only luke warm.

 

Rob....

[nicknorman]

It does sound as though the calorifier coil is blocked, though this is surprising since the engine cooling should be a closed system with antifreeze (= anti corrosion). Or do you have some sort of raw water cooling without a heat exchanger?

 

Anyway, another possibility is that the water pump impeller is disintegrating resulting in very low circulation pressure. It might be worth taking off the calofifier inlet pipe and briefly starting the engine to get an idea of how much pressure there is. Thumb over the pipe as you start to avoid losing a lot of coolant and do it with the engine just warm so you don't burn yourself.

[ROBDEN]

It does sound as though the calorifier coil is blocked, though this is surprising since the engine cooling should be a closed system with antifreeze (= anti corrosion). Or do you have some sort of raw water cooling without a heat exchanger?

 

Anyway, another possibility is that the water pump impeller is disintegrating resulting in very low circulation pressure. It might be worth taking off the calofifier inlet pipe and briefly starting the engine to get an idea of how much pressure there is. Thumb over the pipe as you start to avoid losing a lot of coolant and do it with the engine just warm so you don't burn yourself.

 

I’ve done that and got a good flow to the calorifier but not so good on the return.

 

Perhaps I should explain what I’m trying to do.

 

Vertical calorifier, four fittings that run top to bottom.

 

Top two inlet and outlet to engine.

Bottom two to the Alde.

 

I sometimes get an airlock in the engine to calorifier circuit which is hard to get rid of.

On inspection I noticed that the calorifier inlet is a couple of inches above the engine take off for the feed in.

By swapping the top two for the bottom two and inserting a bleed valve, the inlet from the engine is now a few inches below the engine take off point.

 

Soooo, now the engine to calorifer circuit is in, what was the Alde circuit.

 

The Alde has only been used three or four times in the last three years so I’m wondering if there is crap in the coil due to lack of use.

Incidentally, on testing the new Alde connections I noticed that the rads started to get quite warm after only fifteen to twenty minutes, Whereas before it was a good hour before there was any noticeable heat.

 

If you see what I mean

 

Rob….

[Tony Brooks]

How is the calorifier connected to the radiator circuit? Does it have its own bleed valve at the highest point in the calorifier pipework? Have the radiators been fitted with lock shield valves and if so have they been balanced to ensure sufficient flow goes to the calorifier? Is there a valve controlling the flow through the calorifier. Maybe a diagram might help.

 

Oh, and which Alde?

[by'eck]

Ive done that and got a good flow to the calorifier but not so good on the return.[/size]

 

Perhaps I should explain what Im trying to do.[/size]

 

Vertical calorifier, four fittings that run top to bottom.[/size]

 

Top two inlet and outlet to engine.[/size]

Bottom two to the Alde.[/size]

 

I sometimes get an airlock in the engine to calorifier circuit which is hard to get rid of.[/size]

On inspection I noticed that the calorifier inlet is a couple of inches above the engine take off for the feed in.[/size]

By swapping the top two for the bottom two and inserting a bleed valve, the inlet from the engine is now a few inches below the engine take off point.[/size]

 

Soooo, now the engine to calorifer circuit is in, what was the Alde circuit.[/size]

 

The Alde has only been used three or four times in the last three years so Im wondering if there is crap in the coil due to lack of use.[/size]

Incidentally, on testing the new Alde connections I noticed that the rads started to get quite warm after only fifteen to twenty minutes, Whereas before it was a good hour before there was any noticeable heat.[/size]

 

If you see what I mean[/size]

 

Rob.[/size]

Sounds pretty conclusively that the bottom coil is partially blocked. Would pursue attempting to unblock it.

 

Try and ensure in each case that the hot water feed is to the connection of the upper end of the coil. Inlet and return should be marked.

[ROBDEN]

How is the calorifier connected to the radiator circuit? Via Alde boiler. Does it have its own bleed valve at the highest point in the calorifier pipework? Yes. Have the radiators been fitted with lock shield valves and if so have they been balanced to ensure sufficient flow goes to the calorifier? Yes and yes.Is there a valve controlling the flow through the calorifier Yes. Maybe a diagram might help.

 

Oh, and which Alde? Comfort 2928. Central heating is working well.

Sounds pretty conclusively that the bottom coil is partially blocked. Would pursue attempting to unblock it.

 

Try and ensure in each case that the hot water feed is to the connection of the upper end of the coil. Inlet and return should be marked.

 

Thanks. Off to water point soon. I'll update later.

Rob....

[ROBDEN]

SORTED!!!

 

Back from the water point.

Flushed the calorifier several times, in both directions untill it ran clean.

 

Saw nothing major just very dirty water.

Re-filled the system, bled the air out and started the engine.

Half an hour later, started to get some very hot water from the taps.

 

Now to get on with the important things.........roast lamb and a bottle glass or two of wine.

 

Thanks everyone for your input.

 

Rob....

[ditchcrawler]

SORTED!!!

 

Back from the water point.

Flushed the calorifier several times, in both directions untill it ran clean.

 

Saw nothing major just very dirty water.

Re-filled the system, bled the air out and started the engine.

Half an hour later, started to get some very hot water from the taps.

 

Now to get on with the important things.........roast lamb and a bottle glass or two of wine.

 

Thanks everyone for your input.

 

Rob....

[smileypete]

To help trap air, a 'dead leg' of vertical pipe could be teed in by the calorifier coil top connection, with a bleed screw at the top.

 

With the flow from the engine connected to the calorifier coil bottom connection, trapped air will either rise and go back toward eng, or up through the coil and into the 'dead leg'. Plus having the flow and return crossed over in this way helps stop reverse thermosyphoning.

 

cheers, Pete.

~smpt~