How to route the hoses?

[BobbyB26]

Holy smokes, there's no motor in my boat...just a big empty hole. I'm in the middle of getting my rebuilt put back together and am taking a break to get some stuff down in the bilge while I have no motor in the way. One of the things I'm tackling is moving the RedDot cabin heater to another location so that it is lower than the heat exchanger (PO put in a bad location).

Since it's move the heater time, I'm re-routing the hoses. Here's where the question comes in. I'll set the scene: I've got a RedDot cabin heater and also a hot water heater that pull hot water off the motor. I'd like to lay out the flow to make sure that what makes sense to me, makes sense to all of you????

1. Hot water off of the thermo
2. Hose to the cabin heater
3. Hose from cabin heater to the HWH
4. Hose from HWH back to coolant pump.

This flow seems to be the best to me rather than going thru the HWH first as it seems to me that you would have to wait for all that water to heat up first before you could any cabin heat. Does this make sense to you guys??

B

 

[electricaldoctor]

Holy smokes, there's no motor in my boat...just a big empty hole. I'm in the middle of getting my rebuilt put back together and am taking a break to get some stuff down in the bilge while I have no motor in the way. One of the things I'm tackling is moving the RedDot cabin heater to another location so that it is lower than the heat exchanger (PO put in a bad location).


Since it's move the heater time, I'm re-routing the hoses. Here's where the question comes in. I'll set the scene: I've got a RedDot cabin heater and also a hot water heater that pull hot water off the motor. I'd like to lay out the flow to make sure that what makes sense to me, makes sense to all of you????

1. Hot water off of the thermo
2. Hose to the cabin heater
3. Hose from cabin heater to the HWH
4. Hose from HWH back to coolant pump.

This flow seems to be the best to me rather than going thru the HWH first as it seems to me that you would have to wait for all that water to heat up first before you could any cabin heat. Does this make sense to you guys??

B

I agree with you 100% Bobby. You should have 2 completely separate heating circuits. The HW tank and Cabin Heater should not be in series with each other.

~Ken

 

[KC_Sundancer]

Your set-up would work great for cabin heat right away but something to think about:

First
If you have the cabin heater first you may not get hot enough water in your hot water heater when the cabin heater is running.
Possibly just warm - I'm unsure of how much the temp drop is after passing through the cabin heater when running.
With the hot water heater first you do not have that constant temp drop once the water is heated up like you would with the cabin heater first.

Second
I don't think you could run 2 seperate systems and be sure to have even water flow through both - unless you have twin engines.
With a single I think they would need to be in-line.

Just my thoughts - best of luck!

 

[sbw1]

This should plumbed in a way that allows you to remove and replace hoses that develop leaks in the future when the motor is back in the bildge.

 

[electricaldoctor]

Your set-up would work great for cabin heat right away but something to think about:

First
If you have the cabin heater first you may not get hot enough water in your hot water heater when the cabin heater is running.
Possibly just warm - I'm unsure of how much the temp drop is after passing through the cabin heater when running.
With the hot water heater first you do not have that constant temp drop once the water is heated up like you would with the cabin heater first.

Second
I don't think you could run 2 seperate systems and be sure to have even water flow through both - unless you have twin engines.
With a single I think they would need to be in-line.

Just my thoughts - best of luck!

My Brother has a 33' 1988 Cruisers Inc. with twin 7.4 l. engines that has a H/W tank + a cabin heater plumbed from his Port engine and has a second heater for his cockpit area plumbed from his Starboard engine. The port heaters are not plumbed in series and everything has been working perfectly for the past 20 years.

~Ken :thumbsup:

 

[stevea661]

My water heater is tied to 2, 1/2" lines, one off the intake and one off the water pump. I don't know which is in or out, and I don't have a cabin heater, but I know I could reverse the flow by switching the lines at these two points of connection.

 

[Nehalennia]

Mine Heatercraft heater is on the starboard side behind the mid-berth panel.
You can see that the hoses go up and over the bulkhead to the engine bay.
I installed a aux pump that keeps the flow of hot water flowing and not blowing cold air.

I would just leave it where it is (not knowing exactly where you have it) and install an aux pump.

 

[BobbyB26]

Thanks for all the feed back. I think I've got the direction of the loop figured out. I'm going to stick to routing the hoses to the heater first and then over to the HWH before returning to the motor. This was the way it was done before and makes the most sense too me.....I'm going with the "if it aint broke, don't fix it" approach here.

Todd- Talked to a couple of marine mech's about installing the heater above the level of the heat exchanger. They both brought up the same two issues with doing it this way.

1. The heater can become "air locked". Basically the heater never fills all the way up with coolant. (I have a Red Dot which may a different config than yours) They said that it can fill up partially to the point where the coolant flows across the "bottom" of the heater and then back out again. The "top" of the heater is where the air would be trapped. This leads to pour heater performance. One of the guys said that it could be air locked and you wouldn't even neccessarily know it. The heater would be producing hot air, just not ALL the hot air it supposed too. Makes me wonder how hard this scenerio is on the unit itself.
2. When it comes time to top off your coolant, there will be a head pressure and unless you have some sort of back-flow device you can't get the system topped off.

Thoughts???
B

 

[Nehalennia]

That's why the pump is effective. It makes sure those air bubbles are forced out. It did take about 30 minutes to fill and purge all of the air bubbles, but is the common way Searay installs the heaters too.
Also, my configuration runs the hoses from the hot water side of the engine through the heater, then to the water heater, then back to the engine.