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Wrinkley

2LW 74 Deg thermostat

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Hi

 

Just finished piping up 2LW to the coil in the hot water tank. The water is not really hot enough and so thought about replacing the 60 Deg thermostat with a 74 Deg one. Does any one run the hotter thermostat? Is there a down side to this change? Final question, is this thermostat generally available (what else does it fit)or is it a phone call to Gardner Enthusiast?

 

Thanks for reading.

 

Graham

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I think 70°C is the norm for my Lister - would imagine Gardner would be similar.

 

Have you considered putting the calorifier coil in the bypass cooling circuit before the thermostat. Again I understand this is the norm. The main circuit, when thermostat opens, just brings the skin cooling tank (assuming you have one) into play.

 

If you want a quick engine warm up, in winter for example, you can add a manual gate valve to bypass the bypass circuit (if that makes sense) which has the calorifier coil in its circuit.

 

The alternative as on modern engines is to have twin thermostats providing two cooling circuits.

Edited by richardhula

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You should be fine with a 74 degree thermostat, although I certainly wouldn't go any higher. As long as your skin tank is big enough you shouldn't get any overheating problems. You should be ablt to get a stat from any decent motor factors.

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We have a 4LW with a 73 deg stat. It's been running with that for several thousand hours and never been a problem.

 

I can't comment on availability of the stat because this is a home made stat housing using bits from the scrap yard and a DIY brass block. It uses Ford Fiesta size stats.

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We have a 4LW with a 73 deg stat. It's been running with that for several thousand hours and never been a problem.

 

I can't comment on availability of the stat because this is a home made stat housing using bits from the scrap yard and a DIY brass block. It uses Ford Fiesta size stats.

 

One thing to watch with Gardners is not to let the oil get too hot, probably never an issue with a pottering canal boat engine but it can be if the engine is worked hard, especially if the water temp is maintained fairly high.

The oil bypassed from the relief valve performs important functions, and if the oil is too hot the amount bypassed will reduce, possibly stop altogether in a worn engine. On some engines even if there is a cooler it's fitted in the bypass pipework, so there's a risk of thermal runaway if the oil isn't cooled enough - less oil goes through the cooler, so less is cooled, an escalating process.

So, if your engine is worked hard, oil pressure and temperature gauges are well worth fitting (and keeping an eye on when the work is hard).

 

Tim

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One thing to watch with Gardners is not to let the oil get too hot, probably never an issue with a pottering canal boat engine but it can be if the engine is worked hard, especially if the water temp is maintained fairly high.

The oil bypassed from the relief valve performs important functions, and if the oil is too hot the amount bypassed will reduce, possibly stop altogether in a worn engine. On some engines even if there is a cooler it's fitted in the bypass pipework, so there's a risk of thermal runaway if the oil isn't cooled enough - less oil goes through the cooler, so less is cooled, an escalating process.

So, if your engine is worked hard, oil pressure and temperature gauges are well worth fitting (and keeping an eye on when the work is hard).

 

Tim

 

I took the oil cooler off :)

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Thanks for the replies. I will try an obtain a 74 Deg stat from my local motor factors. First by asking for the item to fit said engine. If they are unable to help I will have to remove the 60 Deg one as pattern.

 

I'll let you know if it makes a difference.

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Hi

 

Just finished piping up 2LW to the coil in the hot water tank. The water is not really hot enough and so thought about replacing the 60 Deg thermostat with a 74 Deg one. Does any one run the hotter thermostat? Is there a down side to this change? Final question, is this thermostat generally available (what else does it fit)or is it a phone call to Gardner Enthusiast?

 

Thanks for reading.

 

Graham

 

I have 17 hrs on my 2LW newly installed, and a similar problem. I have contacted Gardner Enthusiast by email attaching a photo of my thermostat housing to see whether the one they sell will fit, no reply as yet. The calorifier is in the bypass circuit, but the water does not get as hot as I would expect, and takes over one hr to get hot, (but not as hot as I would expect) the engine does not feel particularly hot either but others with similar engines would know better. The pipe to the keel tank does get warm suggesting hot water is getting sent that way as well as via the bypass circuit which I would not expect but the return back to the engine is cold. The engine is not worked particularly hard, more in the range of tickover to (I would estimate) half throttle, because thats all the speed I need out of it cruising or stationary charging

 

Thanks

 

Charles

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I have 17 hrs on my 2LW newly installed, and a similar problem. I have contacted Gardner Enthusiast by email attaching a photo of my thermostat housing to see whether the one they sell will fit, no reply as yet. The calorifier is in the bypass circuit, but the water does not get as hot as I would expect, and takes over one hr to get hot, (but not as hot as I would expect) the engine does not feel particularly hot either but others with similar engines would know better. The pipe to the keel tank does get warm suggesting hot water is getting sent that way as well as via the bypass circuit which I would not expect but the return back to the engine is cold. The engine is not worked particularly hard, more in the range of tickover to (I would estimate) half throttle, because thats all the speed I need out of it cruising or stationary charging

 

Thanks

 

Charles

 

Hi,

 

There was a lot of discussion on the GE forum about this. People having similar problems with the water not heating properly.

 

The water on my 2LW heats up quickly and after a while becomes very hot (use with care).

 

Not sure where you are on the system but I am at Cowroast if you want to come and have a look (well the boat is at Brinklow being repainted until Sept.

 

Not sure what stat I am using as have not had to overhaul this in 5 years of ownership.

 

Leo

 

PS What is your engine stat showing?.

Edited by LEO

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The pipe to the keel tank does get warm suggesting hot water is getting sent that way as well as via the bypass circuit which I would not expect...

 

Why would you not expect that? I thought that was normal?

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Why would you not expect that? I thought that was normal?

 

Because indications are that the engine is running cool, the stat should only open to the keel tank when the engine is hot

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Because indications are that the engine is running cool, the stat should only open to the keel tank when the engine is hot

 

Ahh, I read it as you were surprised it was still going through the bypass (I still do actually :)). In that case, it simply sounds like your stat is either too cold or stuck open.

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The symptoms described by Charles 123 in post #8 above describe my engine and water heating results so far. But reading other posts more closely it would seem some engines have the bypass pipe from the water pump to the thermostat housing disconnected and the flow redirected to the calorifier coil. Am I correct in this assumption? Currently my engine has one connection to the calorifier from the left hand end of the water rail (viewed from the exhaust side of the engine)and the other to the thermostat housing and no break in the bypass pipe.

 

I can confirm the return pipe from the skin tank never gets more than vaguely warm and the oil temperature I have not seen over 40 Deg.

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The flow to the skin tank while the engine is still cold is probably because many thermostats have a weep hole which allows a small flow all the time. Similarly ,on many systems, the bypass will continue to return water to the pump regardless of engine temperature. Add an efficient skin tank to the mix and cold water at the taps is the result.

 

Low domestic water temperature is often an issue with vintage engine powered boats as many simply do not generate a high enough heat load. We recently supplied a Dorman to be installed in a hotel boat (very high hot water demand). It took an 87c stat to produce 60 degrees at the taps. That is towing a butty as well so it is not idling along as many single boats do.

 

It may need a more sophisticated system to cure the problem. You may ,effectively, have two issues, inadequate domestic water heating and engine over cooling/low heat load. I would suggest that there are a couple of practicable options. Perhaps you could consider two level of temperature control. Fit a primary thermostat which would allow the engine to circulate around the bypass until warm and then permit a hot flow to the calorifier. This enables the initial circuit to warm quickly as its not losing warm water to the larger, cooler volume of the skin tank. The primary stat must not have a weep hole in it. We use a common (fiesta et al) stat which are easily available from any decent motor factor. Fit a second ,higher temp stat, and housing which is piped to the skin tank only. This would only open when the engine and calorifier were at the set temperature , and then only when an increase above the primary stat setting occurs. This enables enhanced cooling when things warm up such as thrashing up a river etc. In many cases it would hardly ever open. This would help to maintain the optimum engine temp and help to reduce the risks of glazing and sludging in the engine.

 

A second option is to substitute an Amot valve in place of the primary thermostat. Amot valves are a sophisticated themostatic controller which will maintain the flow at a very well regulated temperature. They can prevent the tap water from overheating to a dangerous level and provide an absolute block to thermal siphoning , which will prevent the calorifier feeding the engine overnight as the motor sometimes becomes a giant heat sink when turned off.

 

The art in it is getting the tap water temp right, allowing the engine to run at optimum temp while having the ability to cool things down when a higher load occurs.You will be surprised how infrequently your skin tank is needed.

  • Greenie 1

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Interesting insight into the workings of thermostats - thanks for that.

 

As mentioned above I intend to have a gate valve in the bypass feed to/from calorifier to initially allow the quickest engine warm up. It should be fail safe as if I forget to close it, the thermostat will eventually open & allow cooling via skin tank.

 

Although untested I'm assuming it will have the added advantage when open of breaking the thermo-syphon effect allowing calorifier to heat soak engine block when not running.

 

My last boat was particularly bad in this respect wasting a lot of electricity with immersion heater trying valiantly to get the engine block warmed up. This until I discovered thankfully that Mr Volvo had installed taps in both legs of calorifier circuit. You still had to remember to turn them off after using engine though.

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Hi Richard, Yes your manual valve will act as an absolute block in your califorier circuit. Way cheaper than an Amot valve but memory dependent! :rolleyes:

Edited by steamraiser2

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Why does thermosyphoning always raise its head in these threads?

 

It only happens if it's all plumbed in wrong.

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Why does thermosyphoning always raise its head in these threads?

 

It only happens if it's all plumbed in wrong.

 

I would imagine its more unfortunate routing of heating circuit or vagaries of heating coils rather than outright wrong plumbing.

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I would imagine its more unfortunate routing of heating circuit or vagaries of heating coils rather than outright wrong plumbing.

 

I suppose you could argue that point. But to me, in a boat, if the coolant pipes from the engine to the calorifier don't both dip down below the heating coils then it's wrong. If they do dip below, thermosyphining doesn't happen :)

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Not properly tested yet but my hot water system may have an inbuilt thermosyphining issue. Not with the piping from the engine as that "dips" to the floor specifically to stop heat returning from the cylinder to the engine. My problem may be with the thermosyphon radiator circuit fed from the back boiler which runs through the second coil in the clarifier. With out introducing a valve I will have to live with it.

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One thing to watch with Gardners is not to let the oil get too hot, probably never an issue with a pottering canal boat engine but it can be if the engine is worked hard, especially if the water temp is maintained fairly high.

The oil bypassed from the relief valve performs important functions, and if the oil is too hot the amount bypassed will reduce, possibly stop altogether in a worn engine. On some engines even if there is a cooler it's fitted in the bypass pipework, so there's a risk of thermal runaway if the oil isn't cooled enough - less oil goes through the cooler, so less is cooled, an escalating process.

So, if your engine is worked hard, oil pressure and temperature gauges are well worth fitting (and keeping an eye on when the work is hard).

 

Tim

I ended up fitting a oil cooler to my 3LW after dropping something in the stank and putting the back of my hand on the sump. We tend to forget that a boat has no air movement over the sump to cool the oil as an automotive engine would have. Gardners fitted oil coolers to marine engines I do not know if it was standard practice on all the marine range.

Jim

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I ended up fitting a oil cooler to my 3LW.Jim

 

I removed the oil cooler from my 4LW :)

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I removed the oil cooler from my 4LW :)

With a 4 your loadings are so low you may not get so hot I also have a 74 stat in I towwed 2 boats up the Thames against yellow boards in 2007 and 10 hours hard running the exaust manifold was glowing red. The Gardner oil cooler cools the oil in the sump I tapped the pressure feed and cooled that.

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I suppose you could argue that point. But to me, in a boat, if the coolant pipes from the engine to the calorifier don't both dip down below the heating coils then it's wrong. If they do dip below, thermosyphining doesn't happen :)

 

 

Thanks' for your last comment. I think you just prevented a 'mistake' here.

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Hi I am new to this, so please bear with me. I found all the discussion on this topic very interesting and helpful, but its still not clear what the optimal set up is. I have recently bought a boat with a 3LW. Its cooling system seems to be plumbed in as per the standard arrangement described in this thread and has the same problems of running cool. Having pondered the current arrangement for a while I am thinking along the following lines:-

 

Key Problems

1. The engine runs cool, all the time. The temperature gauge is a standard electric (Faria) water temperature gauge and barely gets off the bottom stop (50C) evan after running for hours. The gauge needs replacing with a more suitable range so in the interim I have used a cheapo infra red thermometer and after extended running was only just getting to 55C on the top water outlet (so its not the gauge reading incorrectly). I realise this is not too far off the range of temperatures that Gardner specified (60-71C) but I'd like to get to mid 60s and a faster warm up.

 

2. The calorifier is off the bypass line which is fitted with a 22mm ball valve to throttle the flow and encourage water to go via the calorifier. Not convinced much calorifier heating is being obtained given the length of 15mm pipe to and from the calorifier etc. Throttling the bypass flow seems inappropriate to me. I would rather have a decent bypass flow and get the engine uniformly heated after start up. To my mind the calorifier should only come into service when the engine has reached running temperature? The current arrangement would give very cold return to the engine if the calorifier is cold.

 

Other issues

A. No drain valves. What a nuisance if you want to do any work on the system!

B. No vent on the header tank (or anywhere else!). The tank has a loose 2" BSP screw on cap, but a better vent is required. I do not want to rely on a hose coming off if the system overheats

C. Thermosyphoning from Calorifier to engine when engine cold.

D. The header tank line connects to the hot water out from the engine. Probably not much of an issue but I would prefer it connected to the pump suction to ensure no part of the system runs sub-atmospheric.

 

So my proposed actions are:-

 

a. Replace the current thermostats. I suspect they are OK but I assume its a 60C stat. I intend to replace with a 74C stat which, on reading the Gardner manuals, seems to be appropriate to the relatively light loading in this application.

b. Remove the 22mm valve from the thermostat to pump bypass line, and leave the line unrestricted.

c. Re-position the take off for the calorifier to the thermostat main outlet,

d. Fit a flap check valve in the calorifier line to stop thermosyphoning (it will need to be a simple flap valve as I suspect the differential pressure from the pump is quite low.

e. Fit flow control valves in the line to the calorifier and to the skin cooler to allow some adjustment of flows, I propose to use Crane D931 balancing valves, 1.5" (quite big!) to the line to the skin tank and 3/4" on the calorifier line. The combination of 4 turns from open to closed and the style of trim in the valves will provide far more subtle adjustment than using ball valves. I judge some restriction will be required to get the two flows in reasonable balance. The valves have an internal flow measuring orifice so if I can rig a suitable gauge I will be able to estimate flows . These valves are sized so that fully open they will have negligble pressure drops (in case I have misunderstood what is going on)

f. Fit drain valves at the low points.

h. Fit more appropriate range temperature gauge so that 60-70C is near mid scale.

 

So I would welcome views from anyone who has had similar problems or tried any of the above. Any information on the following would be appreciated.

In particular, I am wondering:-

 

Gardner style thermostat operation, in particular the relative opening and closing of the bypass and main valve ports? My manual suggests water flow to the radiator should be seen at 71C, given normal thermostat of 60C, is 71C representative of the fully open temperature?

Expected water flow rate from the pump?

Expected oil temperature. My engine has no oil cooler. The oil seems to be cool (I need to get a measurement). My Gardner manual (42.8) suggests setting the oil pressure regulator when the oil is at 130F (so 54C). Is this a reasonable target temperature?

 

Many thanks

Chris

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