Adjusting vaccum relief valve

Jan Sullins

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I can see that it is an Amtex truckmount with a 20HP Kohler engine. Is the blower a 45 or a 36 ?
If it is a 36 Roots blower then I might set it at 13-14Hg. If it is a 45 I would set it at 14Hg. Actually
a 45 blower can handle like 15 or even up to 16Hg but I wouldn't do that with a 20 HP engine with
that big of blower. I did own a Steamaction Nike 22 truckmount which had a 22 HP Kohler with a 45 Roots blower.
It was direct coupled so the engine and blower ran at the same rpms. I usually ran mine at around 3100 rpms and they
the mfg set the vacuum relief at 14Hg. This was several years ago and I have seen some who are setting vacuum relief
on 45s at 16Hg. Personally running at a proper rpm with an engine with enough horsepower I just don't think
there is much benefit in running your truckmount at over 15Hg.. In order to attain that much vacuum you would likely have
to run it at higher rpms like maybe 3400-3550 rpms. Truckmounts are expensive and so are the components. Just because
we can run them at the highest spec doesn't really mean that it will first benefit us much in the way of better performance.
And second when running at for instance the highest rpms and setting the lift at 16Hg is going to effect the longevity of
the whole system. Prochem usually runs most of their truckmounts with 4M blowers at 14Hg and set the throttle at 3050-3100 rpms.
If it is a 36 blower then really although running it at a faster rpms(3200-3400) should not pose a problem but I would not run the relief valve
at over 13Hg. These high cfm blowers like the 36 and 47 have longer impellers which when running at very high vacuum levels
puts more stress on these blowers.
 

smart n kleen

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I can see that it is an Amtex truckmount with a 20HP Kohler engine. Is the blower a 45 or a 36 ?
If it is a 36 Roots blower then I might set it at 13-14Hg. If it is a 45 I would set it at 14Hg. Actually
a 45 blower can handle like 15 or even up to 16Hg but I wouldn't do that with a 20 HP engine with
that big of blower. I did own a Steamaction Nike 22 truckmount which had a 22 HP Kohler with a 45 Roots blower.
It was direct coupled so the engine and blower ran at the same rpms. I usually ran mine at around 3100 rpms and they
the mfg set the vacuum relief at 14Hg. This was several years ago and I have seen some who are setting vacuum relief
on 45s at 16Hg. Personally running at a proper rpm with an engine with enough horsepower I just don't think
there is much benefit in running your truckmount at over 15Hg.. In order to attain that much vacuum you would likely have
to run it at higher rpms like maybe 3400-3550 rpms. Truckmounts are expensive and so are the components. Just because
we can run them at the highest spec doesn't really mean that it will first benefit us much in the way of better performance.
And second when running at for instance the highest rpms and setting the lift at 16Hg is going to effect the longevity of
the whole system. Prochem usually runs most of their truckmounts with 4M blowers at 14Hg and set the throttle at 3050-3100 rpms.
If it is a 36 blower then really although running it at a faster rpms(3200-3400) should not pose a problem but I would not run the relief valve
at over 13Hg. These high cfm blowers like the 36 and 47 have longer impellers which when running at very high vacuum levels
puts more stress on these blowers.
I ment to say 13 1/2 to 14 hgs. He makes a lot of good points. I think mines at 13 1/2.
 
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Jan Sullins

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I think you will be fine at 13-14Hg. It looks like a 36 blower so that is plenty of lift . Running it at a fairly high rpm will provide optimum
cfms. I don't mean like 3600 rpms which is the limit put on that blower by the mfg. But certainly running it at 3300 or sometimes higher
is going to hurt it. I have a 20HP Kohler with a 3L Sutorbilt blower EZ truckmount which is the same as a Roots 36 and I will run mine sometimes at lower rpms because I may not need to run it at 3300. Maybe it is an upholstery job so I can set it at 2800 rpms and have
plenty of heat and vacuum. With upholstery we use less water and require less vacuum. On the otherhand doing a carpet job with like
250 feet I may run it at 3200 rpms or even higher. Since my engine has plenty of power for the blower I am better able to do that than
if for instance the blower was a 45/4M with the 20HP engine. Takes more horsepower and torque to run the bigger blower. I used to have
a Hydramaster Cross-Fire 3.7 which had a 16HP engine with a 36 Roots blower. Hydramaster made it so there was no throttle adjustment
and it always ran fast . Still that engine didn't last as long as if it were an 18 or 20 HP engine. My personal opinion anyway. .
 

SunnyDays Carpet Cleaning

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I do not know what you mean...can you explain? This is my tm.

thanks
Your is that brass thing with the nut in the center. Full throttle while blocking vacuum. See what gauge is reading. Did you get a manual with that beast. It should tell you how to adjust it.
 

SunnyDays Carpet Cleaning

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I think you will be fine at 13-14Hg. It looks like a 36 blower so that is plenty of lift . Running it at a fairly high rpm will provide optimum
cfms. I don't mean like 3600 rpms which is the limit put on that blower by the mfg. But certainly running it at 3300 or sometimes higher
is going to hurt it. I have a 20HP Kohler with a 3L Sutorbilt blower EZ truckmount which is the same as a Roots 36 and I will run mine sometimes at lower rpms because I may not need to run it at 3300. Maybe it is an upholstery job so I can set it at 2800 rpms and have
plenty of heat and vacuum. With upholstery we use less water and require less vacuum. On the otherhand doing a carpet job with like
250 feet I may run it at 3200 rpms or even higher. Since my engine has plenty of power for the blower I am better able to do that than
if for instance the blower was a 45/4M with the 20HP engine. Takes more horsepower and torque to run the bigger blower. I used to have
a Hydramaster Cross-Fire 3.7 which had a 16HP engine with a 36 Roots blower. Hydramaster made it so there was no throttle adjustment
and it always ran fast . Still that engine didn't last as long as if it were an 18 or 20 HP engine. My personal opinion anyway. .
My Prochem Legend Is thirteen. It's best to read your manual. To much you can cook your blower.
 

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I can see that it is an Amtex truckmount with a 20HP Kohler engine. Is the blower a 45 or a 36 ?
If it is a 36 Roots blower then I might set it at 13-14Hg. If it is a 45 I would set it at 14Hg. Actually
a 45 blower can handle like 15 or even up to 16Hg but I wouldn't do that with a 20 HP engine with
that big of blower. I did own a Steamaction Nike 22 truckmount which had a 22 HP Kohler with a 45 Roots blower.
It was direct coupled so the engine and blower ran at the same rpms. I usually ran mine at around 3100 rpms and they
the mfg set the vacuum relief at 14Hg. This was several years ago and I have seen some who are setting vacuum relief
on 45s at 16Hg. Personally running at a proper rpm with an engine with enough horsepower I just don't think
there is much benefit in running your truckmount at over 15Hg.. In order to attain that much vacuum you would likely have
to run it at higher rpms like maybe 3400-3550 rpms. Truckmounts are expensive and so are the components. Just because
we can run them at the highest spec doesn't really mean that it will first benefit us much in the way of better performance.
And second when running at for instance the highest rpms and setting the lift at 16Hg is going to effect the longevity of
the whole system. Prochem usually runs most of their truckmounts with 4M blowers at 14Hg and set the throttle at 3050-3100 rpms.
If it is a 36 blower then really although running it at a faster rpms(3200-3400) should not pose a problem but I would not run the relief valve
at over 13Hg. These high cfm blowers like the 36 and 47 have longer impellers which when running at very high vacuum levels
puts more stress on these blowers.
It is a 36 roots...for CC I run my 20 hp engine at 2950...I will tune it to 13.5...thanks for the advice.
 

john gerding

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I do not know what you mean...can you explain? This is my tm.

thanks
That brass relief is no bueno... you cant really adjust it at all because the screw just spins and there is nowhere to clamp the screw without damaging the spring... honestly I would be looking for a better relief Bo.. a kunkle valve may be in order..
 
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smart n kleen

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That brass relief is no bueno... you cant really adjust it at all because the screw just spins and there is nowhere to clamp the screw without damaging the spring... honestly I would be looking for a better relief Bo.. a kunkle valve may be in order..
I adjust it fine. I put an extra washer it to make it stronger. There is a spot to put plyers or a wrench on to adjust. The nut also turns.
 

john gerding

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I adjust it fine. I put an extra washer it to make it stronger. There is a spot to put plyers or a wrench on to adjust. The nut also turns.
well then you got lucky and I didnt... neither did mike decker... ben actually quit using that relief... he is now making his own out a piece of pipe thread and a washer...
 

smart n kleen

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well then you got lucky and I didnt... neither did mike decker... ben actually quit using that relief... he is now making his own out a piece of pipe thread and a washer...
I have Bens sitting in my trailer. It leaked always. I have a knuckle that I don't use. This one is ok.
 

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That brass relief is no bueno... you cant really adjust it at all because the screw just spins and there is nowhere to clamp the screw without damaging the spring... honestly I would be looking for a better relief Bo.. a kunkle valve may be in order..
Dang...gonna check my relief and if its close to 13 im leaving it alone.

Are kunkle easy to adjust?
 

john gerding

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Dang...gonna check my relief and if its close to 13 im leaving it alone.

Are kunkle easy to adjust?
kunkle is preadjusted... you tell them the setting you want and they set it...
 
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