4 Way Heater Valve - Anyone have a flow diagram?

[Dave_S]

Hi All,

In this thread: http://www.aulro.com/afvb/technical-chatter/205624-diy-air-con-heater-engine-bay-county-110-a.html

bee utey says "There is a common type of heater valve that has four hose connections and when off allows full bypass flow without the heater. They were used on the '94 V8 RRC, Commodore VS to VY V6 (16mm hoses) and some V8 Falcons (19mm hoses). They have a vacuum actuator which can be operated either by a vac solenoid or a cable after removing the vac pot."

I've taken the air-con out of my County and want to install a standard heater unit sourced from a V8 County. I've pulled that apart to put in a new heater core and insulating foam/gaskets, but it's pretty obvious that it won't seal very well and will get seriously hot if coolant flows through the matrix all the time.

This is especially so as I don't seem to have enough coolant ports at the thermostat housing, so I want to plumb the heater into the same line that cools the turbo (it's an Isuzu turbo). At least the heater will start working pretty fast in the morning :D

Anyway, I'd like to use a 4 way valve like the one bee utey talked about. I can guess that when switched one way, the coolant does a straight pass through, but the other way, it goes in and out of the heater core on its way through the valve. Is this correct, and does anyone have a diagram?

Cheers, Dave.

[Judo]

If you have an Isuzu you can just block flow to the heater core. No need to flow coolant around the heater ports on the thermostat housing. You can just use a single standard inline heater tap then. Does that make sense and help you?

Edit: what I mean is just put a t-piece in the existing lines and see if you get enough flow. Only issue might be the coolant will mostly take the path of least resistance which maybe the turbo. If the turbo is a small hose I reckon you might be ok.

[bee utey]

They are usually marked with arrows for preferred flow direction. Then you can operate the valve with your finger and blow through it to check. Generally the heater connects to the 2 ports on one side, everything else on the other.

[Dave_S]

Judo, unfortunately I'm not sure what you mean. As I understand it, I need coolant to physically flow through the pipes to cool the turbo and lose heat in the heater core, so I need to have positive flow at all times. As the turbo and heater matrix will be on the same line, wouldn't turning the flow "off" at the heater matrix effectively also stop the flow to the turbo?

I thought a 4 way valve would allow the system to be set up in two ways. In the "off" position, coolant flows from the pump/thermostat housing, into the turbo, out of the turbo, into the valve, straight out of the valve and back to the pump/thermostat housing.

In the "on" position, coolant flows from the pump/thermostat housing, into the turbo, out of the turbo, into the valve, into the heater matrix, out of the heater matrix, out of the valve and back to the pump/thermostat housing.

I just want to make sure this is correct before I order a valve. I will try to match the various pipes so everything is the same diameter.

[Judo]

OK, so you want to run the turbo and heater in serial / inline. The coolant flows through the turbo and then through the heater. I couldn't say with 100% certainty that's how the "4 way" tap works. I only count 3 way being necessary.. ??? Why is there 4 connections? If it is 2x2 routes, then I'm not sure that it will actually help you.

bee_utey?

Edit: to summarise - does anyone have a flow diagram? :p :D

[bee utey]

OK, so you want to run the turbo and heater in serial / inline. The coolant flows through the turbo and then through the heater. I couldn't say with 100% certainty that's how the "4 way" tap works. I only count 3 way being necessary.. ??? Why is there 4 connections? If it is 2x2 routes, then I'm not sure that it will actually help you.

bee_utey?
A 4 port valve is functionally equivalent to a 3 port valve and a separate tee piece in the return line (or two nipples on the suction side of the water pump). Take your pick, either way works just fine . 3 port valves used to be found on some Holden V8's of the 70's, 4 port ones are loads more common now.

[Dave_S]

Thanks guys, but I'm still not dead sure how 3 and 4 port valves flow. I'm guessing my description of the flow above was wrong, but don't quite know why. I might just buy a couple of valves and experiment.