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Lister LPWS4 operating temperature range.


rusty69

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I have just changed the coolant in our engine/skin tank,and also connected the calorifier coil to the engine cooling circuit. Previously the calorifier had never been connected. The good news is, we now have piping hot water from the engine. The not so good news is the return pipe from the skin tank remains on the cool side(approx 25 °C)

 

The engine was run for a good 4 hours whilst cruising on the river,with temperature as measured by IR thermometer between 70  °C and 92 °C. The Top of the skin tank reached a maximum temperature of 45 °C, and the bottom, 25 °C.

 

Questions :

Does this appear to be a normal operating temperature range?

What would a typical return temperature be?

Is it possible I have an airlock somewhere?

 

I would expect the return pipe to get a fair bit hotter.The skin tank does seem oversized for the engine, so perhaps this is to be expected, and the situation made worse with the calorifier now in circuit.

 

I did flush the skin tank before I added the new coolant.

 

 

Engine Lister LPWS4,36Hp, build 45.Year 1992.

Skin tank cooling with approx capacity including engine of 78 litres. Water/anitfreeze mix ratio 2:1.

Boat: 69 foot narrowboat.

Engine thermostat, 74 °C (possibly part number 751-40983).

 

 

Thanks as always

Edited by rusty69
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Some thoughts. 

A hot return pipe would be more worrying. Since the skin tank was hotter at the inlet end than the outlet, the tank would seem to be working.

After a 4 hour run, an airlock would have shown itself up by boiling by now. Airlocks tend, in my experience, to manifest themselves quite fast and spectacularly.

I used to have an LPWS4 as well, but intercooled with raw water, and after hours of thrashing upstream on the Thames against really heavy flow, the wet exhaust was never more than tepid to the touch.

You have put more cooling into the system, so it may not be surprising that the engine is not getting very hot. What temperature did it run at before?

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1 minute ago, Stilllearning said:

What temperature did it run at before?

Thanks for your thoughts.

 

The answer is, I don't know,as it has never had a temperature gauge,and I only just got the IR thermometer.

3 minutes ago, Stilllearning said:

You have put more cooling into the system, so it may not be surprising that the engine is not getting very hot.

The engine is getting pretty hot, 92 °C in places.

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3 minutes ago, rusty69 said:

Thanks for your thoughts.

 

The answer is, I don't know,as it has never had a temperature gauge,and I only just got the IR thermometer.

The engine is getting pretty hot, 92 °C in places.

Yes, bet its on the exhaust manifold or thermostat housing. I think that you may have an automotive temperature thermostat in the engine (82 to 88C) but as long as the coolant does not boil it should be fine. What may not be fine is when you get close to boiling water out of the hot taps. Either fit a thermostatic mixing valve to the hot domestic supply or a lower temperature engine thermostat.

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5 minutes ago, Tony Brooks said:

Yes, bet its on the exhaust manifold

Yes.

 

5 minutes ago, Tony Brooks said:

I think that you may have an automotive temperature thermostat in the engine (82 to 88C) but as long as the coolant does not boil it should be fine

I don't know. It had no markings on it except for the temperature, 74°C. When I stuck it in a pan of water, it appeared to be operating correctly.

5 minutes ago, Tony Brooks said:

What may not be fine is when you get close to boiling water out of the hot taps. Either fit a thermostatic mixing valve to the hot domestic supply or a lower temperature engine thermostat.

Point taken. Yes,it is very hot,probably 60 degrees C.

So return pipe to engine from skin tank should not be that hot then?

Edited by rusty69
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Just now, rusty69 said:

Yes.

 

I don't know. It had no markings on it except for the temperature, 74°C. When I stuck it in a pan of water, it appeared to be operating correctly.

In that case apply the infra red thermometer to the top of the thermostat housing or skin tank inlet and get the correct running temperature.  You probably measured heat conducted form the exhaust stubs that have no cooling and run an hundreds of degrees - they can glow yellow under very high and sustained loads.

 

Even if you manifold is a flush fit onto the head it will still conduct exhaust heat up form the gasses.

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1 minute ago, Tony Brooks said:

In that case apply the infra red thermometer to the top of the thermostat housing or skin tank inlet and get the correct running temperature

Thanks Tony.

 

The temperature on the thermostat housing was 70 degrees, falling to 60 degrees at the skin tank inlet. The temperature on other parts of the head was much the same.It was only near the exhaust that it rose to 92 degrees, and that was on full engine load.

 

So a return pipe to engine from skin tank temperature of 25 degrees is acceptable then do you think?

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The return pipe is from skin tank to engine. If we assume you meant that then the skin tank system is dropping the coolant temperature by 45 degrees and as the engine coolant never got to boiling after four hours that should be fine BUT......................unless that four hours was at maximum permitted speed upstream on a river it does not mean your skin tank size is adequate for river work even though its fine for canal use. far too many canal boat skin tanks turn out to be under sized.

 

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6 minutes ago, rusty69 said:

Thanks Tony.

 

The temperature on the thermostat housing was 70 degrees, falling to 60 degrees at the skin tank inlet. The temperature on other parts of the head was much the same.It was only near the exhaust that it rose to 92 degrees, and that was on full engine load.

 

So a return pipe to engine from skin tank temperature of 25 degrees is acceptable then do you think?

Everything else being apparently safely within norms, if it were me, I’d be rather pleased with 25c water going back in to cool the engine. Tony might feel more nervous. Running your engine upstream against serious fresh flow might be a better guide, but as I said earlier, my LPWS4 ran cool even under extreme load.

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6 minutes ago, Tony Brooks said:

The return pipe is from skin tank to engine. If we assume you meant that then the skin tank system is dropping the coolant temperature by 45 degrees and as the engine coolant never got to boiling after four hours that should be fine BUT......................unless that four hours was at maximum permitted speed upstream on a river it does not mean your skin tank size is adequate for river work even though its fine for canal use. far too many canal boat skin tanks turn out to be under sized.

 

 

2 minutes ago, Stilllearning said:

Everything else being apparently safely within norms, if it were me, I’d be rather pleased with 25c water going back in to cool the engine. Tony might feel more nervous. Running your engine upstream against serious fresh flow might be a better guide, but as I said earlier, my LPWS4 ran cool even under extreme load.

Thanks Both.

 

We rarely venture out on fast flowing rivers,though most of our time is spent on the rivers,not the canals.

 

I think, from your replies I can conclude it is working ok.

 

Cheers.

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59 minutes ago, Tony Brooks said:

Yes, bet its on the exhaust manifold or thermostat housing. I think that you may have an automotive temperature thermostat in the engine (82 to 88C) but as long as the coolant does not boil it should be fine. What may not be fine is when you get close to boiling water out of the hot taps. Either fit a thermostatic mixing valve to the hot domestic supply or a lower temperature engine thermostat.

 

Of you fit a thermostatic mixing valve to the hot water output of the calorifier, it will  reduce the amount of hot water you use, effectively giving you a larger calorifier.

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6 minutes ago, cuthound said:

 

Of you fit a thermostatic mixing valve to the hot water output of the calorifier, it will  reduce the amount of hot water you use, effectively giving you a larger calorifier.

Was just gonna start another thread on that.But may as well ask here. Would this be the thing I need:-

 

 

 

https://www.ebay.co.uk/itm/UK-15MM-Thermostatic-Mixing-Blending-Valve-Bidet-Solar-Heater-Shower-Mixer-NEW/123880313265?hash=item1cd7d791b1:m:mGDuCQSHvyp5O3ln6VstgVg

s-l500.jpg

Edited by rusty69
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56 minutes ago, rusty69 said:

Was just gonna start another thread on that.But may as well ask here. Would this be the thing I need:-

 

 

 

https://www.ebay.co.uk/itm/UK-15MM-Thermostatic-Mixing-Blending-Valve-Bidet-Solar-Heater-Shower-Mixer-NEW/123880313265?hash=item1cd7d791b1:m:mGDuCQSHvyp5O3ln6VstgVg

s-l500.jpg

 

Yes, that is the kind of thing.

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I’ll have to check my records for part numbers but my Lpsw4 seemed to be running cool and the thermostat had failed open. I’d assumed this followed an overheating incident due to a failed hose. (Which is perhaps contrary to the lost wax issue Tony B refers too)

 

A well known supplier recommended a replacement 88 degree thermostat which seems fine. 

 

Surecal cauliflowers seem to come with the mixer already fitted but do need setting (well mine did anyway)

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14 minutes ago, jonathanA said:

I’ll have to check my records for part numbers but my Lpsw4 seemed to be running cool and the thermostat had failed open. I’d assumed this followed an overheating incident due to a failed hose. (Which is perhaps contrary to the lost wax issue Tony B refers too)

 

A well known supplier recommended a replacement 88 degree thermostat which seems fine. 

 

Surecal cauliflowers seem to come with the mixer already fitted but do need setting (well mine did anyway)

Interesting. The guy I contacted suggested most people go for the lower temperature stat.

Screenshot 2019-09-15 at 19.22.49.png

So, from the above (from the parts manual),it suggests the 751-40982 is correct for my engine, but not what I have installed.The workshop manual seems to suggest something different though:

 

My calorfier is not a surecal, and doesn't have a mixer. I will install one at some point.

Screenshot 2019-09-15 at 19.32.33.png

Edited by rusty69
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12 hours ago, jonathanA said:

I’ll have to check my records for part numbers but my Lpsw4 seemed to be running cool and the thermostat had failed open. I’d assumed this followed an overheating incident due to a failed hose. (Which is perhaps contrary to the lost wax issue Tony B refers too)

 

A well known supplier recommended a replacement 88 degree thermostat which seems fine. 

 

Surecal cauliflowers seem to come with the mixer already fitted but do need setting (well mine did anyway)

For a fair time after wax stats were introduced they had a sort of pronged catch so it there was an overheat bad enough to expel wax the prongs caught and held the stat open. That would explain why you were advised to change the thermostat. For a number of years now that mechanism seems to have been dropped so now they lose wax and open at a higher temperature. The problem is there is no way of ensuring a particular engine has which type of thermostat although if it is a pronged one the fact it is jammed open is obvious.

 

Personally I would never recommend an 88 degree thermostat on a narrowboat unless I was 100% sure the skin tank size was adequate. That is a typical car temperature where the manufacturer ensures the radiator is large enough.

Edited by Tony Brooks
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On 14/09/2019 at 15:57, rusty69 said:

Skin tank cooling with approx capacity including engine of 78 litres.

What sort of header tank are you using - surely not the standard (Range Rover/MG) one for the amount that would expand?

The reason I ask is our LPSW3 loses coolant as it expands (because of the pipe from the exhaust manifold enters the tank directly under the venting header cap) and I'm toying with the idea of fitting a different header tank as mentioned in other threads on LPWS (either that or I'm getting an air lock).

/G

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30 minutes ago, Psychalist said:

What sort of header tank are you using - surely not the standard (Range Rover/MG) one for the amount that would expand?

I assume it is the standard one that comes fitted to the engine.It sounds like the same pipe arrangement as you have anyway.

Edited by rusty69
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On 14/09/2019 at 15:57, rusty69 said:

Skin tank cooling with approx capacity including engine of 78 litres. Water/anitfreeze mix ratio 2:1.

 

Just noticed the above thanks to Psychalist's quote.

 

Just to point out that skin tank capacity has nothing very much to do with how effective it is at cooling. It is water side skin surface area that is important. A tank measuring 2ft by 2f with a thickness of a yard would hold a lot of coolant but most of it would be well away from the cold outer skin (the hull). Large area, very thin tanks, preferably with internal baffles is the way to go.

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20 minutes ago, Tony Brooks said:

Just noticed the above thanks to Psychalist's quote.

 

Just to point out that skin tank capacity has nothing very much to do with how effective it is at cooling. It is water side skin surface area that is important. A tank measuring 2ft by 2f with a thickness of a yard would hold a lot of coolant but most of it would be well away from the cold outer skin (the hull). Large area, very thin tanks, preferably with internal baffles is the way to go.

Thanks Tony. The tank is approx 88" x 24" x 2". The capacity is accurate, as I measured what came out, and put the same amount back in. I don't know the thickness of plate used in its construction or the tank internal baffle arrangement. I do know that the blacking is scraped off around that area every two years or so and isn't allowed to build up a thickness.

Edited by rusty69
add a bit.
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3 hours ago, rusty69 said:

Thanks Tony. The tank is approx 88" x 24" x 2". The capacity is accurate, as I measured what came out, and put the same amount back in. I don't know the thickness of plate used in its construction or the tank internal baffle arrangement. I do know that the blacking is scraped off around that area every two years or so and isn't allowed to build up a thickness.

So that is about14.6 sq ft and at 4 HP per sq ft it should cool and engine power of about 56 BHP. Scraping the blacking is a very good idea. I just wish more yards did that.

Edited by Tony Brooks
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On 15/09/2019 at 19:25, rusty69 said:

Interesting. The guy I contacted suggested most people go for the lower temperature stat.

Screenshot 2019-09-15 at 19.22.49.png

So, from the above (from the parts manual),it suggests the 751-40982 is correct for my engine, but not what I have installed.The workshop manual seems to suggest something different though:

 

My calorfier is not a surecal, and doesn't have a mixer. I will install one at some point.

Screenshot 2019-09-15 at 19.32.33.png

well I'm confused now...

 

the top extract indicates 751-40982 is correct for my build 47. 

 

the lower extract indicates 854-01222 (LPSW4 build 47) but when I tried to order that from a reputable an well known Lister agent ( I won't give them by name in public forum) they said the correct thermostat was 751-40982....   and so thats what i ordered and fitted.  Checking my records this was 3 years ago, but I think my OCD means I still have the old one , which didn't have any part numbers on (IIRC).   Coincidentally the supplier actually sent me a 751-40983 by mistake and then sent me the 'right' one. 

 

11 hours ago, Tony Brooks said:

For a fair time after wax stats were introduced they had a sort of pronged catch so it there was an overheat bad enough to expel wax the prongs caught and held the stat open. That would explain why you were advised to change the thermostat. For a number of years now that mechanism seems to have been dropped so now they lose wax and open at a higher temperature. The problem is there is no way of ensuring a particular engine has which type of thermostat although if it is a pronged one the fact it is jammed open is obvious.

 

Personally I would never recommend an 88 degree thermostat on a narrowboat unless I was 100% sure the skin tank size was adequate. That is a typical car temperature where the manufacturer ensures the radiator is large enough.

Thanks Tony.  

 

I will check the old stat as I'm sure I kept it 'just in case' but at the time was convinced it had failed open, I would have done the the hand on the 'top hose' type test i'm pretty sure.  I'm also wondering where I got the idea it was an 88C stat - might have been stamped on it, or I might have taken it from the table in the manual (that Rusty69 quotes above).  The temp gauge always seems to hover around the 90C.

 

I'm not sure I understand why the skin size is important with regard to the thermostat temp, if the skin tank isn't big enough , then it isn't big enough and the thermostat would be open anyway.  I wonder if there is an argument that says having a bigger difference between the coolant temp and the 'canal' temp on the skin tank will aid the transfer of more heat ?  My knowledge of thermodynamics is not up to that sort of question...

 

 

 

 

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22 minutes ago, jonathanA said:

well I'm confused now...

 

the top extract indicates 751-40982 is correct for my build 47. 

 

the lower extract indicates 854-01222 (LPSW4 build 47) but when I tried to order that from a reputable an well known Lister agent ( I won't give them by name in public forum) they said the correct thermostat was 751-40982....   and so thats what i ordered and fitted.  Checking my records this was 3 years ago, but I think my OCD means I still have the old one , which didn't have any part numbers on (IIRC).   Coincidentally the supplier actually sent me a 751-40983 by mistake and then sent me the 'right' one. 

 

Yep. That is exactly the same thing that happened to me (except for the mistake bit).The above does suggest that reference should be made to the master parts manual for comprehensive information. I assume the supplier I asked referenced this before quoting the 'correct' thermostat to be the 751-40982.

 

I think mine is the type C2 type with lower skirt. It also has a jiggle pin fwiw.

 

Edited by rusty69
deleted the last bit, already answered
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Just checked. The second supplier I contacted suggested either 751-40982 or 751-40983. Saying most people fit the lower temperature stat.That being the 751-40983. I am surprised it isn't a fixed temperature for canal use.

Edited by rusty69
Changed both to either
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