Frank Wyatt Posted March 30, 2019 Share Posted March 30, 2019 So i think this is the same kind of valve linked to before. I don't think i can use this - its vacuum operated and from what i can tell connects to your dash ac controls - which i do not have. I was hoping someone knew of a mechanically actuated valve to be simple. e.g. i pop the hood and turn a knob or two. And I know AC can be added Anything is possible. I was hoping to get an idea of what level of effort is required. Can i just switch out some parts or is it going to be major headache? I was hoping Steve would comment on this. And I agree, why wouldn't you use the vacuum controlled bypass valve? It's easy to install in your your heater hoses and with the electric vacuum switch and a toggle switch, you'll be able to operate it from inside your truck. The vacuum switch isn't necessary but it's a way to have in cab control of the bypass valve if your truck does not have factory air like my truck. That's the way I'm going when I fix my heater. I was going to use manual shut-off valves until I learned from Steve about that super nice heater bypass valve used on the Ford Explorer and likely other top of the line vehicles. I think it's a super slick solution and will look more well thought out as opposed to looking jerry rigged together. Link to comment Share on other sites More sharing options...
Gary Lewis Posted March 30, 2019 Share Posted March 30, 2019 I'm not sure what you mean, or what you're saying gets bypassed. But simply blocking the heater loop on a 300ci/4.9L will cause problems because the coolant will have nowhere to flow when the t'stat is closed.Good point. I'd forgotten that the 300 doesn't have a bypass in the cooling system as the V8's do. And it would certainly cause a problem to prevent the coolant from circulating in the block prior to the thermostat opening. Thanks for correcting me. But, on a V8 you can put a valve in one of the hoses as they do have a bypass that will still circulate coolant when the 'stat is closed. In fact, that's why the bypass is there.It's always better to put it on the high-pressure side; putting it on the return side will cause high pressure inside the heater core, which will lead to leaks.However, I disagree on this. The pressure in the system is the pressure in the system since the cooling system is a closed, pressurized system Link to comment Share on other sites More sharing options...
Gary Lewis Posted March 30, 2019 Share Posted March 30, 2019 I was hoping Steve would comment on this. And I agree, why wouldn't you use the vacuum controlled bypass valve? It's easy to install in your your heater hoses and with the electric vacuum switch and a toggle switch, you'll be able to operate it from inside your truck. The vacuum switch isn't necessary but it's a way to have in cab control of the bypass valve if your truck does not have factory air like my truck. That's the way I'm going when I fix my heater. I was going to use manual shut-off valves until I learned from Steve about that super nice heater bypass valve used on the Ford Explorer and likely other top of the line vehicles. I think it's a super slick solution and will look more well thought out as opposed to looking jerry rigged together. I agree. But there's a possible upgrade: If you have a single tank get the correct HVAC control for a dual tank and use the tank switch to control the vacuum valve. What better place to have a switch that controls part of the Heating Ventilation & Air Conditioning system than in the Heating Ventilation & Air Conditioning control panel? (I've always thought Ford's placement of the tank switch questionable.) Link to comment Share on other sites More sharing options...
delco1946 Posted March 30, 2019 Author Share Posted March 30, 2019 I agree. But there's a possible upgrade: If you have a single tank get the correct HVAC control for a dual tank and use the tank switch to control the vacuum valve. What better place to have a switch that controls part of the Heating Ventilation & Air Conditioning system than in the Heating Ventilation & Air Conditioning control panel? (I've always thought Ford's placement of the tank switch questionable.) Well I guess I can’t disagree with that logic, But I am very unfamiliar with doing this sort of work so I would need some pretty detailed instructions on how to wire a switch through the firewall, where to mount it, and the actual products needed them selves much like was done with the vacuum four way switch. For example I am not clear if a switch mounted in the cab has a vacuum line going all the way to the switch or if the vacuum hose terminates somewhere in the engine bay where the signal is transferred into an electrical signal and Carried into the Cab via a wire.still learning hear.... Link to comment Share on other sites More sharing options...
grumpin Posted March 30, 2019 Share Posted March 30, 2019 Well I guess I can’t disagree with that logic, But I am very unfamiliar with doing this sort of work so I would need some pretty detailed instructions on how to wire a switch through the firewall, where to mount it, and the actual products needed them selves much like was done with the vacuum four way switch. For example I am not clear if a switch mounted in the cab has a vacuum line going all the way to the switch or if the vacuum hose terminates somewhere in the engine bay where the signal is transferred into an electrical signal and Carried into the Cab via a wire.still learning hear.... I read that the valves can leak, and noticed mine is seeping. Just ordered this improved valve. https://www.amazon.com/gp/product/B07GT22JTC/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1&pldnSite=1 I have this switch, never installed it as I have A/C and when I go to Max A/C the valve bypasses. Plumbed into the same line that closes the Max A/C door. https://www.summitracing.com/parts/vta-11542-vus Edit: Corrected link. Link to comment Share on other sites More sharing options...
Steve83 Posted March 30, 2019 Share Posted March 30, 2019 ...use the vacuum controlled bypass valve? It's easy to install in your your heater hoses and with the electric vacuum switch and a toggle switch...Why use an electric switch to control a vacuum valve to control a vacuum motor? It's simpler to use a vacuum valve, which was standard equipment on '87-early '88 F-series & Broncos; and it would probably fit where the tank/rear window switch goes on a bullnose A/C control. https://supermotors.net/getfile/160699/thumbnail/87-hvaca.jpg The top Left slide is the blower speed switch; the top center button is the compressor clutch switch & indicator; the bottom Left slide is the recirculate vacuum valve (the target of this pic being in this discussion); the other 2 control the temperature & diverter door cables. You'd just remove that valve from that panel, mount it to the bullnose panel, and install a matching knob. Changing the label on the panel would be difficult to make look right, but doable.The pressure in the system is the pressure in the system since the cooling system is a closed, pressurized systemThat would be true if there was no circulation, like in a tank. But since there's a pump forcing the fluid to move, there MUST be suction (lower pressure) on the inlet side of the pump, and higher pressure on the outlet - otherwise, the fluid wouldn't move (Newton's 1st & 2nd laws). Note service procedure #1 in the first TSB in this caption: https://supermotors.net/getfile/262841/thumbnail/09cores.jpg...a switch mounted in the cab has a vacuum line going all the way to the switch...That wouldn't be a switch; it would be a manual vacuum valve, as shown above....or if the vacuum hose terminates somewhere in the engine bay where the signal is transferred into an electrical signal and Carried into the Cab via a wire.Yes, that's what white knight described, but it's unnecessarily (IMO) complicated. This shows how the '80-86 & late-'87-96/7 HVAC vacuum system is built: https://supermotors.net/getfile/741015/thumbnail/hvacvac.jpg For each vacuum motor diaphragm (one of the motors has 2 diaphragms), there's a corresponding section of the mechanical valve in the control panel. You'd just add another mechanical valve to control the vacuum motor on the heater hose valve. Link to comment Share on other sites More sharing options...
grumpin Posted March 30, 2019 Share Posted March 30, 2019 ...use the vacuum controlled bypass valve? It's easy to install in your your heater hoses and with the electric vacuum switch and a toggle switch...Why use an electric switch to control a vacuum valve to control a vacuum motor? It's simpler to use a vacuum switch, which was standard equipment on '87-early '88 F-series & Broncos; and it would probably fit where the tank/rear window switch goes on a bullnose A/C control. To me it's easier. Wire in a switch and use it when I want to. Do you mean to get this vacuum switch and install it where convenient? Edit: Add question. Link to comment Share on other sites More sharing options...
Frank Wyatt Posted March 31, 2019 Share Posted March 31, 2019 ...use the vacuum controlled bypass valve? It's easy to install in your your heater hoses and with the electric vacuum switch and a toggle switch...Why use an electric switch to control a vacuum valve to control a vacuum motor? It's simpler to use a vacuum switch, which was standard equipment on '87-early '88 F-series & Broncos; and it would probably fit where the tank/rear window switch goes on a bullnose A/C control. To me it's easier. Wire in a switch and use it when I want to. Do you mean to get this vacuum switch and install it where convenient? Edit: Add question. That's my plan when I fix my heater Grumpin. Steve, that would eliminate the need for the toggle switch and electric vacuum switch, but the OP, IIRC, and my truck does not have the HVAC vacuum control panel, they are heat only, no factory air or the accompanying bits and pieces. My truck has two cables, one for the underhood blend door and the other switches from defrost to floor heat. Link to comment Share on other sites More sharing options...
Steve83 Posted March 31, 2019 Share Posted March 31, 2019 ...my truck does not have the HVAC vacuum control panel, they are heat only, no factory air or the accompanying bits and pieces.That vacuum control valve could be mounted almost anywhere - maybe where the factory fog light switch goes, or just to the bottom lip of the dash. If you're good with a dremel, you could put it into your heat-only control panel. Link to comment Share on other sites More sharing options...
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