Topic: Heater shut-off valve


len47merc    -- 07-10-2017 @ 11:20 AM
  After a fairly lengthy few drives with the '47 this past Saturday to multiple shows in ~95 degree weather I was giving consideration to shutting-off water flow to the heater with the heater control valve on the passenger head. Typically I've always left it open to minimize sedimentation in the heater core and take advantage of what little additional cooling is afforded by running the coolant through the full system. Plus, when keeping the heater doors closed it's negative contribution to the comfort factor on hot days is marginal so left it open and flowing.

Feeling the air coming through the vent though I could definitely tell it was picking up on a bit more heat from the heater core than I recalled so the consideration came to mind of closing the valve. Before doing so, a few questions:

1) What do most of you all do - leave it open or close it off during the summer months?

2) Have any of you had any problems cycling it off/on, etc., either from mechanical or performance perspectives (not only with the valve but any other related parts and overall cooling)?

3) Any other concerns with using the valve as intended?

Thanks in advance -

Steve

This message was edited by len47merc on 7-10-17 @ 11:22 AM


woodiewagon46    -- 07-10-2017 @ 4:01 PM
  I always close mine at the first hot spell. As you know, if it's not shut, the heater still has hot water flowing thru it. It can get awful hot in the summer. I never thought about sediment build up.


len47merc    -- 07-10-2017 @ 4:49 PM
  Thanks. Although it had sat for in excess of 40 years, I was stunned at how much muck came out of the heater core and how long I had to flush it to get it to run clear. Perhaps it's not a issue for a car that is routinely driven - just thought I'd ask the question to see if there were any concerns here or elsewhere. Corrosion? Sedimentation? Build-up? Higher engine operating temps of measurable significance? Couldn't find any tangible info on this when searching the Forum so thought I'd ask the dumb question.

I bit the bullet and closed it today and will develop my own data set over July (hottest month of the year here) thru September.

Still welcome any comments/concerns/observations/experience on this. Thanks woodiewagon46 for weighing in.

Steve


Drbrown    -- 07-10-2017 @ 9:52 PM
  My '47 has the traditional manual on-off valve you talk about on the passenger side head but it also has an aftermarket flow control valve (photo) in the return heater hose between the heater core and lower radiator hose. It is operated by the choke cable with knob next to the heater switch. It permits reducing the coolant flow or turning it on or off. I understand this type control kit is still manufactured (don't remember who).

Personally, considering the relatively small quantity of fluid the heater circuit contains, I doubt whether having the heater flow circuit turned on or off affects engine performance. The engine-radiator coolant temperature should be unaffected and only in a minor way if the heater fan is running.

I usually leave the coolant circuit turned on, mostly because (1) I forget about it and (2) I don't notice any heat coming from it without the fan is running.

This message was edited by Drbrown on 7-10-17 @ 9:56 PM


TomO    -- 07-11-2017 @ 6:15 AM
  I leave mine open all of the time. I did not notice any improvement in engine cooling when I installed the heater. Sediment accumulation should not be a problem, if you remember to open the valve when you back flush and change your coolant.

Tom


len47merc    -- 07-11-2017 @ 7:27 AM
  Thanks guys. As noted I too have left mine open all the time including the drives to the prior two Eastern National Meets in July & August temps, so my perspective has always been it's better to leave it open as I've never perceived any adverse interior heat contribution with the heater doors closed. Think I'll try it this and next month for personal edification anyway and will report back with any results of significance. The '47's maintenance schedule calls for a change/flush after this summer as well so good time for this personal test - doesn't sound from your responses there are any serious concerns you have that I should be aware of.

The original valve itself (as well as the repops) has me somewhat concerned about its robustness and ability to take (repeated) cycling on and off without creating a leak, even under the relatively low 4 lbs of system pressure. Given woodiewagon46's comments it sounds like the risk of this is adequately low enough to relieve my concern (somewhat anyway).

Thanks again -

Steve


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