Gardner 3LW and Eberspacher diesel heater

[Clanky]

When i run my Eberspacher for hot water/central heating the engine also gets hot, is this normally how they are plumbed in? I understand that diesel heaters were intended for preheating engines, is this normal on a narrowboat or could it be that the thermostat on on the engine is possibly stuck open allowing the hot water from the eberspacher to reverse circulate? i've only owned the boat for a few months so i'm unsure if this is normal with classic engines. My previous isuzu engined boat didn't do this. Thanks

[Tony Brooks]

32 minutes ago, Clanky said:

When i run my Eberspacher for hot water/central heating the engine also gets hot, is this normally how they are plumbed in? I understand that diesel heaters were intended for preheating engines, is this normal on a narrowboat or could it be that the thermostat on on the engine is possibly stuck open allowing the hot water from the eberspacher to reverse circulate? i've only owned the boat for a few months so i'm unsure if this is normal with classic engines. My previous isuzu engined boat didn't do this. Thanks

 

Not knowing exactly how your boat is equipped and plumbed, but I think the most likely cause is that you have a twin coil calorifier.  One coil heated by the Eber, and the other by the engine. When the calorifier is hot, the hot domestic water heats the engine coil and causes it to thermo-syphon. Hence, the engine getting warm. If I am correct, then a flap type plumbers non-return valve would probably stop it, and the calorifier will probably stay hotter for longer.

 

This is conjecture until far more information/photos are provided

[Clanky]

thats great info Tony, thank you.

[Markinaboat]

Not disimilar to my setup. There is one header thank for the engine (3LW) and heating/hot water circuit with pipes running from  both systems to the tank. There is a gate valve (installed by Charles Mills) on the pipe to the engine thermostat. This allows to the engine to warm up quicker (theoretically) and as stated above helps prvent heat loss from the calorifier back to the engine. LW's do not need pre-heating, that's why they have the cold start button on the injector pump. HTH.

[matty40s]

Normal for Gardners, the bonus being in Winter it never has to start from ice cold.

My thermostat has the calorifier take off before the stat, allowing hot water straight away, only when the engine gets really hot does the stat to the skin tank open.

[Clanky]

4 hours ago, Markinaboat said:

Not disimilar to my setup. There is one header thank for the engine (3LW) and heating/hot water circuit with pipes running from  both systems to the tank. There is a gate valve (installed by Charles Mills) on the pipe to the engine thermostat. This allows to the engine to warm up quicker (theoretically) and as stated above helps prvent heat loss from the calorifier back to the engine. LW's do not need pre-heating, that's why they have the cold start button on the injector pump. HTH.

i have a header tank for the engine and one for the eberspacher? There is an inline screw isolating valve just after the thermostat like yours. If i were to shut this valve then should this prevent the HW circulating around the engine and keep the water hotter for longer as atm the engine is just acting like a big radiator, as long as i remember to open it again when running the engine of course?

[Stilllearning]

3 minutes ago, Clanky said:

i have a header tank for the engine and one for the eberspacher? There is an inline screw isolating valve just after the thermostat like yours. If i were to shut this valve then should this prevent the HW circulating around the engine and keep the water hotter for longer as atm the engine is just acting like a big radiator, as long as i remember to open it again when running the engine of course?

And put a note next to the ignition switch to remind you to open the valve each time you start the engine!

[Clanky]

Just now, Stilllearning said:

And put a note next to the ignition switch to remind you to open the valve each time you start the engine!

HaHa, i've just this minute been and done that 🤣 👍

[matty40s]

Your diesel heater will have an entirely different set of piping to the cauliflower than the engine set, and yes, it should have it's own header tank.