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Old 18 September 2018, 12:57   #1
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Honwave Pressure tester and T38IE

I have just inflated my new Honwave T38IE using the Itiwit electric pump. I was very pleased with how it inflated the boat and the the Halkey Roberts adapter that came with the pump twists into the Honwave valve and locks very well so you can walk away and let it pump away while you do other things. I set the pressure to 0.8 bar for the floor (Well actually 11.6 PSI) and it correctly stopped at this point.

I just tested the pressure in the floor (boat is at home on the lawn and very little temp change) with the supplied Honwave test meter which looks excellent quality and works well but it only shows 0.65 Bar

I was wondering which is likely to be more accurate and other peoples experiences.

Comments appreciated

Dennis
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Old 18 September 2018, 13:24   #2
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Most gauges will have a 5-10% band which may be stated in the documentation. But it would be odd to have both at their opposite +/_ extremes (.8-.08=.72 & .65+.065=.715) but it is possible therefore that both are "correct!"
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Old 18 September 2018, 13:44   #3
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Quote:
Originally Posted by Bigplumbs View Post
and it correctly stopped at this point.
Quote:
and works well
you don't really know either of those things.

In my experience pumps get hot when working (and compressing air generates heat in the same way that decompressing it makes "cold"), so even if the ambient temperature hasn't changed things might have cooled back down to "room temp" a bit. Everytime you connect a different gauge you will loose a little air - but probably not enough to explain it. If you put the pump back on now what does it say the pressure is?
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Old 18 September 2018, 14:33   #4
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you don't really know either of those things.

In my experience pumps get hot when working (and compressing air generates heat in the same way that decompressing it makes "cold"), so even if the ambient temperature hasn't changed things might have cooled back down to "room temp" a bit. Everytime you connect a different gauge you will loose a little air - but probably not enough to explain it. If you put the pump back on now what does it say the pressure is?

The pump stopped at the setting I set and It pumped up the whole Sib without any problem and without having to hold the pipe in ie I could walk around doing other things. That is what I meant by worked well.

Took some more readings now it has 'settled'

On the Floor

The itiwit cut out as set to 11.6 psi and cuts immediately it sees this. Once left a little while it reads 11.2 psi

On the Honwave test valve it reads 10.6 psi at this settled point

So actually the two are a lot closer than I first thought.

I think I will therefore set the Itiwit to say 12.2 psi and I think I will be where I need to be at around 11.6 psi.

Dennis
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Old 18 September 2018, 18:10   #5
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End of the day these are cheep gauges and as poly says pumps generate heat 11.6-11.2 is what I expect I never use it a absolute pressure if the tube rings when I hit it job done as the actress said if it's hard that will do
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Old 19 September 2018, 07:46   #6
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End of the day these are cheep gauges and as poly says pumps generate heat 11.6-11.2 is what I expect I never use it a absolute pressure if the tube rings when I hit it job done as the actress said if it's hard that will do
The gauge that came with the Honwave looks very good quality indeed. I think the Itiwit one just needs it set a bit higher because it cuts off the second it hits the pressure you set
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Old 19 September 2018, 09:10   #7
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The gauge that came with the Honwave looks very good quality indeed. I think the Itiwit one just needs it set a bit higher because it cuts off the second it hits the pressure you set
My Sevylor pump overshoots the set pressure slightly then when it cuts out it is seen that the correct pressure has been reached.
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Old 19 September 2018, 09:48   #8
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Of course without calibrated test equipment we never really know which of our gauges is the correct one.

When my Bravo 12v pump is set to 800mbar for the air floor it cuts out correctly on its own display at the 800. I have two dial gauges supplied by Zodiac (one branded Zodiac and the other Bravo) and when either of those is put on seconds after the Bravo pump has cut out they read close to the same at almost 900mbar. Once cooled and settled however the pressure on the dial gauges reads 850mbar. By the time it's been on the water a few minutes dial gauges read 800mbar.

So by accident or design the Bravo pump extra pressure over its digital display ends up with the perfect pressure.
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Old 19 September 2018, 10:04   #9
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interesting reading it mentions accuracy class i suspect the gauges we use are at the bottom in terms of accuracy,as said if not calibrated regular you won't know only a guide IMO

https://blog.beamex.com/how-to-calib...ressure-gauges
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