Luke Warm Heater [Archive]

shunra

08-21-2008, 11:53 AM

I am having problems with my heater. It is at best luke warm. It is the same temperature at all RPMs. I did the installation myself including the y pipe. There is no temperature difference between idle and full throttle. The engine is the RTP1 and I have the heater core installed behind the drivers kick pannel. I also installed a shower that shares the same hot water pickup and the water coming out of the shower is hot enought to be uncomfortable.

The engine runs at about 150 degrees. I stopped by my MC dealer and asked for a replacement thermostat and the new one is stamped with 140 degrees. Is this the normal thermostat for this engine? It is in a 2002 X-star by the way.

Sodar

08-21-2008, 11:59 AM

Search Heater Y-pipe on the boards. Low heater temp is normal at idle and the Y-pipe helps to improve the heat at low RPMs.

How did you install the y-pipe? If you search, there is a diagram of the install. It requires one line to be capped at the engine and attached to the pipe.

bigmac

08-21-2008, 12:01 PM

How and where did you install the Y-pipe?

dsoby

08-21-2008, 12:07 PM

Heater hose/core could be clogged. Try back washing it.

Sodar

08-21-2008, 12:15 PM

Here is the link (http://www.mastercraft.com/teamtalk/showpost.php?p=121511&postcount=11) to the correct way to install the y-adapter.

jwroblew

08-21-2008, 12:17 PM

My heater has always been luke warm as well. So after reading about the Y pipe, it looks like all it does is restrict the return flow so the heat exchanger has more time to get the heat out of the water. Why could you not restrict the flow back into the engine recalculating pump ang get the same result?

jwroblew

08-21-2008, 01:06 PM

Or is it the fact that your putting warm water back into the system by feeding the water back into the cold water intake, keeping the inlet temp up at idle

P-hat_in_Cincy

08-21-2008, 01:14 PM

Or is it the fact that your putting warm water back into the system by feeding the water back into the cold water intake, keeping the inlet temp up at idle
I don't think that would be the case. That would just make your thermostat stay open longer.

JLeuck64

08-21-2008, 01:28 PM

The Y-Pipe works on the same principle as the venturi in a carb.

Think of it this way, as the fresh water is drawn into the raw water pump there is low pressure. When you add the Y-Pipe you are tapping into that low pressure, which helps to increase the flow of water through the heater core at idle RPM's. The pressure difference across the heater core is what moves the fluids containing our much needed warmth, which we desparetly need to stop sh-sh-shivering.;)

Luke warm is about the best amount of heat I have ever experienced from a boat...

Just enough to take the edge off but it will never be close to what a car heater feels like.

shunra

08-21-2008, 01:35 PM

How and where did you install the Y-pipe?

The only difference between the pictures in the link and my y-pipe is where it is placed on teh raw water line. My y-pipe is in the portion of the line that is lying horizontial in the bilge - not on the vertical piece as shown in the link. Do you think that could be the problem?

Heater hose/core could be clogged. Try back washing it
I have already tried this. I diconnected the two heater hoses at the motor and was able to blow them out. I blew into them and was able to get air through. It didn't seem like too much restriction but I guess I don't really know how much to be looking for. BTW it has always been luke warm right from when I installed the heater at the beginning of this season

Anybody know what kind of temperature the engine should be operating at?

dsoby

08-21-2008, 01:41 PM

jwroblew

08-21-2008, 03:13 PM

The Y-Pipe works on the same principle as the venturi in a carb.

Think of it this way, as the fresh water is drawn into the raw water pump there is low pressure. When you add the Y-Pipe you are tapping into that low pressure, which helps to increase the flow of water through the heater core at idle RPM's.

What happens when the thermostat is closed, instead of circulating water like when hooked up to the water pump, wouldn't you pump the heater core / engine dry? When the thermostat is closed doesn't the water from your raw water pump just get dumped into the exhaust manifolds?

shunra

08-21-2008, 03:23 PM

Your Y connector is supposed to be between the raw water pump and your thru-hull water intake. If it is on the other side of your pump, you have water pressure at both ends of the system. This would definitely cause your problem.

My Y pipe is between the raw water pump and the thru-hull. It is just a little different than the picture in the link posted on page 1. Mine is installed about mid way between the thru-hull and the raw water pump. The one in the link shows it installed very close to the raw water pump, on the vertical part of the line. Mine is insalled where the line is horizontal.

Sodar

08-21-2008, 03:25 PM

My Y pipe is between the raw water pump and the thru-hull. It is just a little different than the picture in the link posted on page 1. Mine is installed about mid way between the thru-hull and the raw water pump. The one in the link shows it installed very close to the raw water pump, on the vertical part of the line. Mine is insalled where the line is horizontal.

That should make no difference. As long as the Y- is facing the correct direction and it is placed between the water intake and water pump, you should be just fine.

jwroblew

08-21-2008, 03:55 PM

shunra

08-21-2008, 04:07 PM

That should make no difference. As long as the Y- is facing the correct direction and it is placed between the water intake and water pump, you should be just fine.

Yeah that is what I think too - I don't think it is a Y pipe problem.

So that makes me wonder then what the problem is. Maybe my motor is just running to cool. I have never seen it get above 150 degrees.

The temperature of the air from the heater is cool enough that I have never been abe to convince anyone to use it :D It really doesn't warm you up - is that all I can expect from these heaters? It is the 3 port unit from Heatercraft with 2 hot tubes.

Sodar

08-21-2008, 04:11 PM

What hot water source are you using?

My MCX runs in the 160 range, but I doubt 10 degrees is going to make a substantial difference.

shunra

08-21-2008, 04:25 PM

What hot water source are you using?

My MCX runs in the 160 range, but I doubt 10 degrees is going to make a substantial difference.

I am using the port that is right beside the thermostat on the top of the engine. P-Hat's picture below shows the port I am using. It is the open hole on the right side of the image. It is the same port that I use for the hot shower.

bigmac

08-21-2008, 04:57 PM

You said shower and heater. Assuming that indeed that Y pipe is facing the right way, maybe the shower fitting is creating a flow problem.

In that regard, I note that most people try to keep the shower and heater circuits separate rather than T-ing the shower from the heater lines. In that regard, you could consider connecting the shower to the OTHER manifold fitting (where the temp sensor is) and put that sensor on a T-fitting. Alternatively, you could use one of your engine block drains as the hot water source for the shower.

As to the raw water intake fitting, consider using a special Y-fitting designed specifically for raw water line attachment of both the shower and the heater, but keeping them separate.

http://www.heatercraft.com/images/products/Medium/H400441-med.jpg

http://www.heatercraft.com/ProductInfo.aspx?productid=H400441

jwroblew

08-21-2008, 05:17 PM

What happens when the thermostat is closed, instead of circulating water like when hooked up to the water pump, wouldn't you pump the heater core / engine dry? When the thermostat is closed doesn't the water from your raw water pump just get dumped into the exhaust manifolds?

Alright I am in idiot, after thinking about it, if the thermostat was closed and you started to pump the engine dry, the engine temp would go up and reopen the thermostat....:rolleyes:

But if all the Y-Pipe does is increase the flow through the heater why would you not want the hole in the 5/8" Y line bigger than the small pin hole that is there? The bigger the hole the more flow, the higher temp in the heater core correct?

bigmac

08-21-2008, 05:24 PM

But if all the Y-Pipe does is increase the flow through the heater why would you not want the hole in the 5/8" Y line bigger than the small pin hole that is there? The bigger the hole the more flow, the higher temp in the heater core correct?
Venturi effect depends on a certain size hole.

TX.X-30 fan

08-21-2008, 07:44 PM

Venturi effect depends on a certain size hole.

That's exactly what my wife said. :D

chico

08-21-2008, 09:16 PM

The y- fitting has a restriction in it to reduce the flow thru the core,if that restriction was not there the raw water pump would short circuit the water in a loop,starving the engine,if you ran it without the restrictor the engine will overheat,how many btu is your heater core?

TX.X-30 fan

08-21-2008, 09:27 PM

,how many btu is your heater core?

I think we should leave the British out of this. ;)

Holman J.B.F

08-22-2008, 01:40 AM

is it a original y-pipe or did you made your own?...sounds like the hole inside the Y might be to big.That causes the engine to run a little cooler +/- 10-15

duh,....didn.t read page 3

2000XPSD

08-22-2008, 10:06 AM

is this the right Y-fitting?
http://www.heatercraft.com/ProductInfo.aspx?productid=H424

***...$40???

bigmac

08-22-2008, 10:09 AM

is this the right Y-fitting?
http://www.heatercraft.com/ProductInfo.aspx?productid=H424

***...$40???

Or this one (http://www.skidim.com/prodinfo.asp?number=H424)for $34.50...

jwroblew

08-22-2008, 10:19 AM

I think I am going to make my own. A wye (Y) pvc pipe from home depot, some barb fittings, and a ball valve on the 5/8" line to restrict flow, and I should be in business for about $10 to $15. Plus with the ball valve I will be able to experiment with how open the restriction needs to be to get the most out of the heater with out over heating the engine, and as an added bonus I will be able to shut flow off to the heater in the summer.

shunra

08-22-2008, 11:35 AM

how many btu is your heater core?

I have the 40,000 btu/h heater from heatercraft. The 3 outlet one.

is it a original y-pipe or did you made your own?...
It is the heatercraft y-pipe, and it is insalled in the correct direction

sounds like the hole inside the Y might be to big.That causes the engine to run a little cooler +/- 10-15
I thought that at first too, but I bought a stock thermostat from my dealership and it is stamped with 140 degrees, which would probably make for a 150 degree operating temp. Would 10-20 degrees make that much difference anyway?

Does anyone else with a RTP-1 know what temperature their engine runs at?

shunra

08-22-2008, 11:48 AM

Alternatively, you could use one of your engine block drains as the hot water source for the shower.

I think I might try that. The only reason I didn't initially put it there was b/c I was afraid of crud ending up in the heater/shower lines. I think I will leave the shower on the top of the engine and try moving the heater down to the block drain. Any idea what type of threads are in that drain? (my boat is at the lake)

As to the raw water intake fitting, consider using a special Y-fitting designed specifically for raw water line attachment of both the shower and the heater, but keeping them separate.

http://www.heatercraft.com/images/products/Medium/H400441-med.jpg

http://www.heatercraft.com/ProductInfo.aspx?productid=H400441

I think heatercraft recommends that pipe for showers on boats with closed cooling. My boat is fresh water cooling, so my cold water intake for the shower is on the other side of the raw water pump. It is a 90degree 'T' fitting that goes on the pressure side of the raw water impeller. I think this is what the shower instructions said to do.

Holman J.B.F

08-22-2008, 03:30 PM

shunra

08-22-2008, 04:11 PM

strange,.
maybe an air lock inside the core? - blocked (folded) heaterhose?
a 160 stat might help -

iirc the cold water line from the shower has a bal valve to prevent hot water comming back into the engine,...maybe you have a pressure fall thru that valve in that case the circulation pump/waterflow diagram doesn,t have enough pressure to feed the heater core.

other than these i,m out of options.

Ahhh....you got me thinking. It might be possible that the cold water supply for my shower is going through the shower mixing valve and out the hot water side and therefore diluting the hot water supply. Since my heater also uses the same hot water supply I am getting a mix of cold and hot water going to the heater. I think I can test the theory by closing the cold water tap on the shower mixing valve. If this turns out to be the problem I can just seperate the shower and heater hot water supply lines as bigmac mentioned and it should solve the problem.

jwroblew

08-22-2008, 05:20 PM

...If this turns out to be the problem I can just seperate the shower and heater hot water supply lines as bigmac mentioned and it should solve the problem.

Or you could add a one way check valve into hot water line going to the shower, this way you don't have to re-plum your system.

shunra

08-22-2008, 05:26 PM

Or you could add a one way check valve into hot water line going to the shower, this way you don't have to re-plum your system.

Yeah that would work too. Probably better since if I just move the heater line, I might still be pumping cold water into the top of the engine whenever I am running.

This weekend I will verify that this is indeed the problem by shutting off the mixer valve. If it fixes the problem I will start looking for a check valve. Home Depot?

shunra

08-25-2008, 11:22 AM

Well, that was it. The cold water supply from the shower is feeding back through the mixer valve, out the hot water side and into the heater core. As soon as I turned off the cold water tap on the shower the temperature of the heater went up substantially. Looks like I am off to look for a check valve.

Thanks for the help everyone.