Volvo Penta MD2030 Cooling system flow direction

[MBH]

Hi,
Hoping someone here can help with this one. I have an MD2030 fitted into a Bavaria 32 and piped into a QL water heater calorifier. Sadly the engine was fitted by a total muppet in Plataria last year who made countless cock ups - not least of which leaving an uninsulated cable hanging off the alternator output shorting to the engine block!!
One problem I am left with however is not getting any water coming out of the water heater on the hot tap. I have checked the QL manual and the cold feed and hot water outlet are piped correctly - however the QL water tank manuals show a distinct flow direction for the inlet and outlet pipes from the engine.
Here lies the problem I cannot find any reference to which way the water flows in and out of the Penta water pump in order to be sure it is piped in the correct direction. Another worry is that there doesn't seem to be any escape valves fitted to the water tank, it is piped directly into and out of the water pump on the engine. Would welcome thoughts and advice.



Thanks in advance.

[alamoana]

[alamoana]

#18 is the hot water outlet from engine to calorifier

[MBH]

Hi Alamoana,

Thanks for the response. I had seen the diagram you refer to but if you look very carefully there is a line on the drawing that implies that the connectors will fit either port. I then found another diagram that seemed to imply the right hand port (looking at the front of the engine) might be the outlet. I extrapolated that if there was a thermostat on this line its purpose would be to prevent flow through the water heater until the engine was warm. Which just kind of lead to increased confusion.

[DougR]

The second 2030 photo shown is the way the engine should be plumbed... Hot water leaves the engine on the fitting toward the heat exchanger side of the engine, and returns to the suction side of the pump thru the fitting on the injection pump side of the engine.

The thermostat "valve" which is shown in the drawing is supposed to open only after the engine heats up, but they were more trouble than they were worth and I would suggest not using one. But I would install ball valves in the two lines to and from the hot water tank so that it can be taken out of the circuit if necessary.

My recollection of the flow thru the QL heater is that it doesn't matter which way the antifreeze flows into or out of the tank, as it is just a simple pipe loop inside the tank. But on the cold and hot water side, the cold water needs to enter the tank on the bottom and exit on the top... And it looks like you are plumbed correctly. The only thing that might be an issue is if the tank is higher than the engine, and then it might airlock and antifreeze won't flow thru the heating coil. A bleed valve might be needed if that is the case.

There should be an over pressure valve on the tank, located on the end close to the electrical connection cover. If you look closely I think you will find it.

I can't see any reason why water should not flow when you open the tap, assuming you have pressure to the tank. It's just an empty tank.....put pressure on one fitting and water will flow out the other fitting.

I installed one of these QL heaters on my own boat about 20 years ago, directly plumbed to a Perkins 4-108 and then a VP D2-55, and ( knock on wood) it has been trouble free that whole time. Warms up fairly quickly and easily holds temp overnight.

[MBH]

Hi DougR,

Thanks for the fantastically detailed response. Gives me the confidence to move on to the next step of fault finding. I need to flush and clean the cooling system anyway so will take the opportunity to remove and flush the tank and make sure all is well - I suspect there's a blockage somewhere in the system but at least I can re-plumb it correctly now.

Thanks.

BR - MBH.

[Cowpoos]

The hottest water leaves the water pump on the engine and goes to the heat exchanger on the right hand side of the engine.