Wesmar RS-400 Overheating when system disabled but not when it's enabled

[Candide]

I have a Wesmar/Hydraulic–Fins/RS-400 stabilizer and it overheats (Tank gets to 150F after 1.5 hours) when I cruise with the system in disabled mode. If I cruise with it enabled for the same amount of time system only gets to 122F and says there. Cooling water flow through heat exchanger looks good and the pressure is at 750PSI. Does not make any sense to me that enabled or disabled would make any different? Anyone seen this? Why is it overheating in disabled mode?

 

[twistedtree]

I don't know that system at all, but it sounds like when disabled, fluid isn't flowing through the heat exchanger the same way it is when the system is enabled.

Do you have a hydraulic schematic of the system?

 

[Candide]

Item 9 is the pressure relief. I believe that when engine is running fluid is pumping all the time and every now and then the spools allow flow when moving the fins. Otherwise, 9 is the pressure relief that keeps the system at 750PSI.

 

[twistedtree]

This isn't making much sense to me either. If the system builds pressure, which apparently it does, it will be by way of the relief valve and heat will be generated accordingly. So it's no surprise there is heat. But I would expect it to be pretty much the same whether the fins are being used actively or not. I guess if the fins are moving, some portion of the hot fluid is diverted out to the actuators with cooler oil coming back, so I can see it having some cooling effect, but I would not think a lot.

The only explanation I can come up with is that your system is right on the cusp of overheating, and the cooling effect of operating the actuators is just enough to keep temps within range.

I see there is a filter in this diagram. Has that been changed recently? Perhaps it is generating back pressure and producing additional heat?

Otherwise I think I'd focus on the seawater cooling side of things, especially considering it's propensity for fouling. What is your source of cooling water? Is it s dedicated cooling circuit with thruhull, strainer, pump, discharge? Or is main engine cooling water diverted to the hydraulic cooler? If main engine water, is it drawn off before or after it cools engine components, all of which will in turn heat the cooling water. I downloaded an RS400 manual and it said the cooling system is designed for max 80F water temp. You can tell Wesmar is based out of the PNW What is your sea water temp? Have you ever opened up the cooler, removed any zinc fragments, and rodded out the cooling tubes?

Oh, and I forgot to ask what is probably the most important question. Was this previously working fine, and recently started doing this? Or has it always been this way? Or this is the first time you have used the boat this way so might just be discovering it for the first time?

 

[Bmarler]

Like TT says, pumping oil across a relief valve makes heat. Without oil going out to the actuators it’s just recirculating from the tank/pump/relief/tank. The less oil making the loop means more heat retained. It’s only a thirty degree rise (ish) but enough to be concerned about. I would think either an aux cooler or a bypass valve would fix it.

 

[twistedtree]

Like TT says, pumping oil across a relief valve makes heat. Without oil going out to the actuators it’s just recirculating from the tank/pump/relief/tank. The less oil making the loop means more heat retained. It’s only a thirty degree rise (ish) but enough to be concerned about. I would think either an aux cooler or a bypass valve would fix it.

But according to the schematic, all the oil goes through the cooler, all the time, whether the actuators are active or not. That's why it's so puzzling to me. The only difference when the actuators are active is that some portion of the oil goes through both the actuators and the cooler, as opposed to only the cooler.

The most likely explanation seems to be a cooling system that is right on the cusp of meeting the cooling needs, and that a good cleaning and servicing will fix the problem.

 

[Bmarler]

But according to the schematic, all the oil goes through the cooler, all the time, whether the actuators are active or not. That's why it's so puzzling to me. The only difference when the actuators are active is that some portion of the oil goes through both the actuators and the cooler, as opposed to only the cooler.

The most likely explanation seems to be a cooling system that is right on the cusp of meeting the cooling needs, and that a good cleaning and servicing will fix the problem.

Absolutely agree the cooling is marginal as designed. That’s why the 80f water temp rating. It won’t take much to push it past it’s limit as you mentioned. Cooler passages lightly fouled, etc…
I didn’t see if it shows if all ports blocked when deactivated, but I’d assume it was that way so they lock into position.
I wonder if there’s a clutch option on the pump. That would actually be the best way to deactivate the system if the fin ports block.

 

[twistedtree]

How is your pump driven? Belt? Engine PTO? Gearbox PTO? The only place I've seen a clutched pump is off of a larger gearbox.

When the fins are deactivated, apparently the dump valve remains closed causing the system to build pressure. If the dump valve were left open then little to no heat would develop. But I'm guessing they build pressure to hold the fins in place, as you suggest.

 

[Candide]

Pump is a PTO off engine so run and moves fluid whenever the engine is running.

At this point I am thinking I should pull the cooler out and ensure it is clean and not plugged restricting the cooling. There is little else in the system so really no idea what else to look at.

 

[Bmarler]

Pump is a PTO off engine so run and moves fluid whenever the engine is running.

At this point I am thinking I should pull the cooler out and ensure it is clean and not plugged restricting the cooling. There is little else in the system so really no idea what else to look at.

that's the right place to start. if that doesn't fix it, i would add a small cooler in line to gain some heat transfer. a small one like a transmission cooler would work just fine.

 

[twistedtree]

Pump is a PTO off engine so run and moves fluid whenever the engine is running.

At this point I am thinking I should pull the cooler out and ensure it is clean and not plugged restricting the cooling. There is little else in the system so really no idea what else to look at.

I agree that a thorough service of the cooling system is the first step.

Where does the cooling water come from? Off an engine, and if so, where in the flow path through the engine? Or is there a dedicated thruhull, pump, and discharge?

 

[Bmarler]

that's a good thought. where's the best place to put the cooler in line? the earlier it get's the raw water the more heat it removes. but then the engine or transmission gets warmer water.
i wonder what wesmar recommends?

 

[sunchaser]

Not necessarily related to cooling - have you changed your stabilizer oil filter recently? Have you called Wesmar?

 

[twistedtree]

that's a good thought. where's the best place to put the cooler in line? the earlier it get's the raw water the more heat it removes. but then the engine or transmission gets warmer water.
i wonder what wesmar recommends?

Ideally you would have a separate cooling loop with it's own intake and discharge so that it can be sized and operate without interference from, or intefereing with the engine cooling. But that's not always practical.

I think I would alternately pull it off right after the raw water pump, but you would likely need a valve or something to control the flow so it doesn't divert too much from the engine. I'd put it there for two reasons:

1) If the engine cooling system starts to get blocked up, it won't starve the hydraulic cooling for flow, or deliver hotter water.

2) In general I think it's key to tap in upstream of any zincs so that broken zinc fragments can't block the water supply line. I know people who have had shaft seal water taken off downstream of zincs and ended up with wrecked shaft seals because the water supply got blocked off by shedding zincs.

 

[Greg QS]

I have a westmar rs 600 system. My system pulls and returns different. Mine pull directly from the tank then charges the system with 2 pumps. The Westmar cooling system is independent of the engines. Check your water flow volume, intake, cooler, and pump.

Dum question, Why are you running in disabled mode? If moving it should be active. My understanding is Disable mode is for docking or to lock out the find due to a problem and installing the lock out pins. I don't think it is supposed to be used the way you are using it. My manuals are on the boat I can check over the weekend for you if you wish.

 

[Candide]

All of this feedback has been great and helped. Very much appreciated. I have now flushed the unit with barnacle buster and it was clearly dirty. We will have to wait and see if that helps.

Doing more digging and found the following. There is a relief valve that bleeds the pressure back to the tank when the pressure hits 750-850 PSI. There is also a bypass solenoid valve that is normally open which allows the fluid to be pumps into the manifold and then back to the tank which prevent the fluid from heating up from the relief valve when the system is turned on. When the system is on fluid either move through the relief valve heating up or to the fins which likely does not heat up the fluid much.

When in disabled mode or in clam water most fluid moves through the relieve. When in rough water more fluid goes to the fins and less to the fins and likely why we don't heat up when system enabled.

My conclusion is that everything seems to be working correctly mechanically but the thermodynamically my heat exchanger was dirty and not doing what it should. Now cleaned will have to wait and see what happens at the end of the month when we move the boat. I at least know that if it heats up I can just turn off the breaker and the bypass should stop it from getting any hotter.

 

[sunchaser]

I've some experience in maintaining the Wesmar cooling systems. I'd suggest you remove the HXer and drop in a bucket of recommended cleaner juice.. That way you can see that it is perfectly cleaned out and not fret about damaging other sensitive engine cooling parts.. Do it every two years.

Change the zincs every year or so as wear dictates. When was last time the oil was changed? If you have a Vickers pump, the seals may start weeping after a few years indicating a new set are needed.

 

[Candide]

Conclusion: The heat exchanger was cleaned. Oil filter was recently changed. Confirmed that when the breaker for the stabilizer is on that the system pressures up which means in standby or engaged mode the pressure relief is in play and will heat up the oil. Did a 10-hour run a few days ago with the stabilizer doing lots of work. Only headed to 112F. Today did another 10-hour run back and water was very calm, and it heated up to 114F. Turned the breaker off to have the bypass kick in and the system cooled down 5 Deg F in only 5 minutes and down to 97F (engine room temperature) in about 30 minutes. System is back in action, and I learnt a lot. Thanks everyone.