calorifier/engine/collant system issue

[silverbuttocks]

HI All,

 

They're great boats, aren't they? The gift that just keeps on giving...

 

and so, another year another set of issues...

 

Over xmas hols i fitted new rads for a newly installed back boiler. I also finally sorted out our paloma plumbing, which was plumbed into the hot water system along with the calorifier (as one system, and therefore did not work properly, as the paloma would pump hot water into the calorifier!). But now both the rads and the hot water are not connected to the calorifier (i have put stop ends on both sets of pipes coming from it). When i ran the engine for three hours a coupe of days ago when I turned the engine off there was a hissing and quite a bit of steam coming from the engine well. When I opened it it seemed like it was coming from nearby one of the pipes going into or out of the calorifier.

 

Am I being stupid? OK, I didn't drain the two systems that were previously plugged into it (but the rads have always been turned off at a tap new to the calorifier as they were blocked (hence new ones). But there appears to be also be a pipe going from the calorifier to a skin fitting in the engine compartment so I would have thought that if it was too hot then steam and hot water should be ejected from this? Could the hot water from the engine that heats up the calorifier element be getting too hot because there is no flow into and out of the calorifier to take the heat away? If the latter how can I block this off?? I might start using the calorifier again soon as I think I will connect up the rads again and have it feed in (with taps to turn off when engine not in use) to the back boiler-heated central heating system.

 

Does any of that make sense?????

[Captain Fizz]

No, not a lot of sense.

How many indirect heating coils are there in the calorifier.

The engine coolant used for water heating, should be on it's own closed circuit.

It does sound as if you have a right mish mash of a system.

Can you post a diagram or some photo's of the installation?

[nicknorman]

It sounds like the engine coolant is too hot, rather than the hot water in the calorifier being too hot. Typically the engine is cooled by a skin tank, or maybe by raw water cooling (ie water sucked in from the canal/river then expelled into it again typically via the exhaust). It sounds as though the engine is not being cooled adequately, could be various causes depending on the type of cooling, such as stuck thermostat, air lock in the skin tank circuit, raw water cooling inlet blocked, or even a defective engine water pump. If you give us some more info about how the engine is cooled, we may be able to help.

 

Perhaps you have disturbed the engine coolant loop, lost some coolant thus creating an airlock?

[silverbuttocks]

No, not a lot of sense.

How many indirect heating coils are there in the calorifier.

The engine coolant used for water heating, should be on it's own closed circuit.

It does sound as if you have a right mish mash of a system.

Can you post a diagram or some photo's of the installation?

 

sorry, not explaining it very well. but luckily, in an attempt to understand the plumbing a little better i drew a schematic of the calorifier plumbing which I will try and attach to this post. i will attach a photo of the engine and relevant pipework a bit later. basically there is a outlet and inlet from the engine to the calorifier (two of the pipes numbered 1, 2 or 3 on the schematic). the third one of these goes from the calorifier to the skin fitting. i have blocked off the pipes to the rads and the hot water system.

 

It sounds like the engine coolant is too hot, rather than the hot water in the calorifier being too hot. Typically the engine is cooled by a skin tank, or maybe by raw water cooling (ie water sucked in from the canal/river then expelled into it again typically via the exhaust). It sounds as though the engine is not being cooled adequately, could be various causes depending on the type of cooling, such as stuck thermostat, air lock in the skin tank circuit, raw water cooling inlet blocked, or even a defective engine water pump. If you give us some more info about how the engine is cooled, we may be able to help.

 

Perhaps you have disturbed the engine coolant loop, lost some coolant thus creating an airlock?

 

hi. i don't think there's an issue with the engine or coolant system - it just started doing this since i blocked up the pipes to the rads and hot water.

 

it's a BMC Thorneycroft 1.5

[Taslim]

As the above posts gizzus some photos or diagrams of your layout.

 

If as Nick sugests you have somehow cocked up with the engine cooling loop that can be expensive. Diesels like hot but not over temperature.

 

Ed as, as ever, I was beaten by a faster man an the key board but if what you say is right (don't doubt it is) where is the heat to make the 'steam' comming from?

Edited January 3, 2014 by Taslim

[silverbuttocks]

how do you add attachments to these posts??????

As the above posts gizzus some photos or diagrams of your layout.

 

If as Nick sugests you have somehow cocked up with the engine cooling loop that can be expensive. Diesels like hot but not over temperature.

 

Ed as, as ever, I was beaten by a faster man an the key board but if what you say is right (don't doubt it is) where is the 'steam' comming from?

 

hiya. i haven't messed with anything on the engine side of the calorifier so that's not the issue. all i have done is block off the pipes to the rads and hot water system (the pipes to rads were already turned off).

 

can't see how to add attachments to these posts

[PaulJ]

Have a look here-http://www.canalworld.net/forums/index.php?showtopic=55758

Its how I worked out to do it (Thanks DH)

[Taslim]

how do you add attachments to these posts??????

 

hiya. i haven't messed with anything on the engine side of the calorifier so that's not the issue. all i have done is block off the pipes to the rads and hot water system (the pipes to rads were already turned off).

 

can't see how to add attachments to these posts

See PaulJ for posting flicks info. I can't get the knack m'self.

 

So your prob isn't on the engine side. Look the circulation from your back boiler to rads and how sound your pipe stop ends are.

 

Sorry if this sounds stupid but you havn't acidentaly made it a closed system have you?

 

My comments are not intended to cast doubt on your skills, just baced on some foul ups I have made.

[MtB]

I'd look at it the other way around if I were you. The engine didn't overheat until you made these changes, so the chances are you introduced the problem by making these changes.

 

The task is to figure out how the changes made the engine cooling system cease working.

 

Maybe the changes you made are not those you think you have made... Is it feasible to reverse them then test the engine cooling again?

 

MtB

[silverbuttocks]

hi everyone

 

i expect i have been an idiot, but i did think about this for some time and can explain my reasoning!

 

this is the schematic, if it works:

 

 

taslim, i have indeed made a closed system, but this is why i thought it was ok.

 

the water feed to the rads (on the left of the schematic) was turned off when we bought the boat as the rads were knackered. the water feed to the hot water system (on the right) has always been on though (but also linked to the paloma, so it didn't work well - the paloma is great now that it doesn't feed water into the calorifier!). but now i have closed it off by simply cutting the pipes (which works at the business end and we now have hot water). however i have not created a loop at the end of the severed pipes. BUT, i didn't think this would matter because we haven't always ran the hot water when the engine is running and nothing bad happens (the engine isn't overheating MtB - just steam coming from pipes going from engine to calorifier - i think!! i need to try it again and check). i realise that what was left in the two systems (rads and hotwater) would have nowhere to go, but the rads have been like that since we bought it with no issues. I thought that the pipe (one of the 1, 2 and 3 pipes on the schematic) that went to the skin fitting would just expel this as steam or hot water, but thinking about it maybe this is for overheating of the actual hot water element from engine. So, should I put a loop on the hot water system (on the right), but thing is there's no pump to pump it around so how would this solve the problem??? Or is there a way I can put the calorifier out of action until I decide whether to use it to supplement the back boiler???

[Tony Brooks]

The red cap is almost certainly a pressure relief valve that should only "blow" when the calorifier heats up. This will vent a SMALL amount of warm/hot water. If it is ejecting loads then either it is faulty (try twisting the red cap a few times to clear the seat) or the pump pressure is higher than the valve pressure.

 

I think the calorifier coil may well "short" out the supply to the rads so they do not get hot. You are asking a lot of the engine water pump to provide sufficient flow - especially as you probably have a skin tank in parallel with what you show.

[silverbuttocks]

The red cap is almost certainly a pressure relief valve that should only "blow" when the calorifier heats up. This will vent a SMALL amount of warm/hot water. If it is ejecting loads then either it is faulty (try twisting the red cap a few times to clear the seat) or the pump pressure is higher than the valve pressure.

 

I think the calorifier coil may well "short" out the supply to the rads so they do not get hot. You are asking a lot of the engine water pump to provide sufficient flow - especially as you probably have a skin tank in parallel with what you show.

 

hi tony

 

wow, this is getting confusing.

 

i am not getting water, or steam, or anything from the red cap. i only see the steam in the engine compartment coming from somewhere either from the pipes where they go from the engine bay to the calorifier or around that area. it's only happened once and i didn't see exactly.

 

i'm not sure about your last comment. do you mean that when the rads were working the engine pump supplied water to the rads?? this makes sense as i have never found any signs of a pump. to clarify, this has been turned off (at the taps) since we have had the boat as one of the rads was knackered. if i get it back up and running it would be to connect to the loop of an existing back boiler with pump, in which case i guess i would need to connect the hot water loop to it rather than the old rad/engine water pump system (as then I would have two pumps and i would be pumping hot water from the stove to the engine!!).

 

but i still don;t know why something is over-heating. the rads have never been on so it can't be that. in which case it has to be the hot water pipes that i have just stop-ended. but why would this matter?? should there be a loop instead on the old hot water pipes??

[davidb]

so are you saying you cut the pipes at the forward bulkhead so there is now no fresh water in the calorifier? so maybe the heat from the engine has now dried all the remains of the fresh water in there, but it is strange that it came out as steam unless the relief valve was stuck open. I assume the relief valve just vents into the engine room.

[Tony Brooks]

The red cap is probably on top of the PRV which in turn has a hose connected to it. This hose vents into the engine room bilge, but in other boats may go through the hull.

 

Please, please DO NOT connect a solid fuel stove's back boiler to the engine cooling circuit. I know some have, but most engines run with the system sealed pressurized to up to 15PSI. If the stove ever boiled you would be in a potentially dangerous situation. You would also HAVE to fit a 12V pump to ensure the water in the stove boiler was constantly circulated to dump heat and prevent boiling.

 

I know using ginseng heat for radiators seems attractive but once a stove is involved my view is its far better to use a twin coil calorofier (1 coil for the stove and one for the engine) and then pipe the rads to run by gravity circulation so you avoid extra electricity consumption.

 

I am not clear about the whole system or what you are trying to achieve so can not say much more.

[silverbuttocks]

so are you saying you cut the pipes at the forward bulkhead so there is now no fresh water in the calorifier? so maybe the heat from the engine has now dried all the remains of the fresh water in there, but it is strange that it came out as steam unless the relief valve was stuck open. I assume the relief valve just vents into the engine room.

 

hi, yes. i cut them actually inside the boat, about half way down. so no, there is no water being heated up by the calorifier, but there must still be water from the engine going round the actual element (sorry, don;t have the tech vocab for this!). so it seems like the water that was left has just vented. just seems odd that it didn;t vent out of the pipe to the skin fitting...

 

i will run the engine again tomorrow and see what happens. is there anything you think i should do to be on the safe side?

The red cap is probably on top of the PRV which in turn has a hose connected to it. This hose vents into the engine room bilge, but in other boats may go through the hull.

 

Please, please DO NOT connect a solid fuel stove's back boiler to the engine cooling circuit. I know some have, but most engines run with the system sealed pressurized to up to 15PSI. If the stove ever boiled you would be in a potentially dangerous situation. You would also HAVE to fit a 12V pump to ensure the water in the stove boiler was constantly circulated to dump heat and prevent boiling.

 

I know using ginseng heat for radiators seems attractive but once a stove is involved my view is its far better to use a twin coil calorofier (1 coil for the stove and one for the engine) and then pipe the rads to run by gravity circulation so you avoid extra electricity consumption.

 

I am not clear about the whole system or what you are trying to achieve so can not say much more.

 

hi tony. guess i wasn't clear. i was saying that i definitely would NOT attach the engine coolant system to the rads/back boiler. The back boiler already has a pump and obviously this would be a bad thing. however, the hot water supply that used to go to the taps in the boat could be attached as these are a closed system that are not connected to the engine and do not have a pump (well, they used to be connected via the water pump on the boat, but i have disconnected them now.

[Tony Brooks]

All I can say is that your diagram shows the radiators and thus almost certainly the back boiler connected to the engine cooling circuit.

 

On what info we have I still suspect the PRV might be sticky so it dribbles a little hot water into the engine bay. Give the knob a good few twists with the domestic water pump ON and then try again.

[silverbuttocks]

All I can say is that your diagram shows the radiators and thus almost certainly the back boiler connected to the engine cooling circuit.

 

On what info we have I still suspect the PRV might be sticky so it dribbles a little hot water into the engine bay. Give the knob a good few twists with the domestic water pump ON and then try again.

 

maybe i didn't say. i would like to emphasise, since i have fitted the back boiler and new rads these are all on a separate system and are not connected to the calorifier at all. they have been switched off at the taps and i have put a loop in that end of the rad system...