# Chapin 20v sprayer pulsing



## doanster (Apr 3, 2018)

I picked up a 20v sprayer here in canada a few months ago (expensive here) but was tired of my pump sprayer. first time i used it - got half of my 7000 sq ft yard done with my humic/ fulvic/ kelp mix and the pump would pulsate and then it would run for a few seconds and stop. Contacted chapin and they sent me a replacement sprayer. Put on my red teejet airx 110 tip and had no issues until today. Today, about half way thru a broadcast spray the pump started pulsing. turned it off - drained the tank - flushed with water twice - took the tip off - switched batteries, etc - nothing seemed to fix it.
Has anyone had similar issues and if so - how did you fix? Or am i just twice unlucky? 
this tip has always been on the sprayer so i cant see that as an issue - even pulsed today with no tip on at all!

any help appreciated Rick


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## kur1j (Jul 2, 2017)

@doanster I'm not having the same issue you are but I'm having a slightly different problem with it priming itself.

Is it not running at all (running out of pressure)? Possibly getting plugged up with something? Just guessing here.


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## Ecks from Tex (Apr 26, 2018)

doanster said:


> I picked up a 20v sprayer here in canada a few months ago (expensive here) but was tired of my pump sprayer. first time i used it - got half of my 7000 sq ft yard done with my humic/ fulvic/ kelp mix and the pump would pulsate and then it would run for a few seconds and stop. Contacted chapin and they sent me a replacement sprayer. Put on my red teejet airx 110 tip and had no issues until today. Today, about half way thru a broadcast spray the pump started pulsing. turned it off - drained the tank - flushed with water twice - took the tip off - switched batteries, etc - nothing seemed to fix it.
> Has anyone had similar issues and if so - how did you fix? Or am i just twice unlucky?
> this tip has always been on the sprayer so i cant see that as an issue - even pulsed today with no tip on at all!
> 
> any help appreciated Rick


What products have you been applying when it started malfunctioning? Were you applying humic/fulvic/kelp products each time?

What may be happening here is the products you mentioned in your post are actually quite thick and can bog down the Chapin pump. The pump will pulse when there is insufficient liquid in the chamber, thinking that the hose trigger is not depressed and therefore pumping is not necessary.


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## gene_stl (Oct 29, 2017)

My Fimco LG-5-p sprayer was pulsing and the cause was two different leaks. The leaks would drop the pressure and the 35psi on demand switch would run the pump to pump it back up.

One leak was because the barb fitting on the output of the pump which is normally under pressure did not have the hose clamp tightened enough. I gooed some silicone caulk onto it and tightened it up and it stopped leaking there. That time it wasn't pulsing just running and I could see the leak the first time I turned it on after assembling it.

Then later out in the lawn it started pulsing. After saying the magic words I finished what I was doing and flushed it and discovered that it was leaking from the pump itself. Like the hose clamps the minimum wage or slave characters that assembled the pump (A Fimco Gold 1 gpm 35 psi unit) did not tighten the screws that clamped the pump head to the motor housing. I applied silicone to the flat surfaces (you have to be careful not to over apply it) and tightened it up correctly and now it does not pulse nor leak. I have sprayed three or four five gallon loads since fixing it and I think I finally have it beaten into submission. This is the pump:
https://www.amazon.com/Fimco-Diaphragm-Flammable-Combustible-Operations/dp/B000NYYW9S/ref=sr_1_1?ie=UTF8&qid=1529302007&sr=8-1&keywords=high+flo+gold+series+pump


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## Colonel K0rn (Jul 4, 2017)

kur1j said:


> @doanster I'm not having the same issue you are but I'm having a slightly different problem with it priming itself.
> 
> Is it not running at all (running out of pressure)? Possibly getting plugged up with something? Just guessing here.





doanster said:


> I picked up a 20v sprayer here in canada a few months ago (expensive here) but was tired of my pump sprayer. first time i used it - got half of my 7000 sq ft yard done with my humic/ fulvic/ kelp mix and the pump would pulsate and then it would run for a few seconds and stop. Contacted chapin and they sent me a replacement sprayer. Put on my red teejet airx 110 tip and had no issues until today. Today, about half way thru a broadcast spray the pump started pulsing. turned it off - drained the tank - flushed with water twice - took the tip off - switched batteries, etc - nothing seemed to fix it.
> Has anyone had similar issues and if so - how did you fix? Or am i just twice unlucky?
> this tip has always been on the sprayer so i cant see that as an issue - even pulsed today with no tip on at all!
> 
> any help appreciated Rick


I can offer some suggestions to both of you since I swear I've had most of the problems with my 24V that you guys are experiencing. As for the pump not priming, I found that when I turn it on, and it's going to the boom, instead of the wand, it won't prime. I switch it to the wand, and it starts spraying, and it's problem solved. What I've started doing is leaving about 1 1/2 gallons in the tank after I'm done cleaning it out, and just running water through it to flush it out. When I'm ready to use it again, it works fine since it's got water again.

To answer the question that you have doanster, both of the failures that I've had with the pump were related to the pressure switch on the pump. I took the cover off of the end of the pump, and connected both of the red wires together, and just bypassed the pressure switch altogether. When I have my sprayer on, I intend for it to be spraying out of the nozzles, and since I've done that, I've had no problems. *knocks on wood*

Try those solutions out and see if it helps you with your problems.


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## gene_stl (Oct 29, 2017)

Lack of priming can also be a symptom of a leak or a bad seal because instead of sucking up the juice it just sucks air. This would be a leak before the input side of the pump.

Jumpering the pressure switch is one solution but running it that way is likely to damage the pump before too long. It probably isn't great for the battery either. It would require you to be more careful (as you say running it open). If it was pulsing you should look for a leak.

I went to Chapin's website and on the 20 volt back pack and 24 volt walk around they have no information on the pumps whatsoever. They don't list pumps as spare parts. they seem to be replacing them when they act up. No parts part numbers nor exploded views.

Fimco customer service admitted that they had problems with stuff coming out of the factory not tightened and that I should go ahead and tighten to my hearts content. :roll:

If anyone has either of these two units open maybe you could post some photographs of the pumps. Did the ones that pulsed show evidence of leaking? The amount of the leak is proportional to the amount of pulsing (short cycling).


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## doanster (Apr 3, 2018)

Priming is not my issue as i always leave water in the tank when not in use. As far as the product sprayed - have sprayed it many times before without issue - is a liquid additive that is mixed at 2-4 oz per 4 gallons of water - so barely noticeable in water - no leaks anywhere - will take pump apart tonight and look at pressure switch - will take a picture and post.


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## doanster (Apr 3, 2018)

Ok - so i took the sprayer apart tonight - pics detail what i found. The pump is a modified delavan powerflow 2200 (delavan is headquartered in Minnesota ) the pressure switch is generic with some wierd casting or wear marks on one side - small pcb out by itself ties the pressure switch, power switch and motor together electrically. Motor is and open cage 18v dc motor but is protected because it is inverted inside the protective dome so if their was a leak - fluid would flow down and away.

trying to figure out next steps - maybe contacting delavan and getting another pressure switch - any suggestions appreciated.


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## Colonel K0rn (Jul 4, 2017)

Have you contacted Chapin to have them send you a replacement? They're usually very good about sending replacement parts to customers.


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## doanster (Apr 3, 2018)

This is my second backpack sprayer from them - same issue as first one - and they do not list or offer any repair parts as the pressure switches and circuit boards are soldered - not considered consumer replaceable.


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## gene_stl (Oct 29, 2017)

I think speaking with customer service at Delavan would be my next move. Sometimes companies don't want to get in the middle in situations like this but on the other hand they may want to know what is going on.

I have a similar situation going with a defective and very overly complex fuel gauge on my Hustler zero turn. The gauge is made by a company called Kelch but they won't help end users other than providing their fuel gauge brochure.

This pump looks very similar to the Fimco I have. It also has a microswitch and diaphragm although they are oriented a little differently.

I was thinking , how can it pulse if it is not actually leaking and I am thinking it might have some kind of bad check valve or diaphragm in the pump. It pumps itself up, till the pressure switch opens and then the pressure starts back flowing into the unpressurized supply line. That would be solely the fault of the pump and Delavan should be interested in that. That said it doesn't take a very big leak to make them pulse since water is not compressible. The amount depends on the spring constant and the area of the diaphragm that operates the microswitch. On the Fimco pump it was like two drops

Did it work any better for you, after you put it back together? Also what are those holes in the pressure switch cover? Those shouldn't be there I don't think.

Pump is externally and spec wise almost identical to the Fimco in my drag around. It would drop right in and is only about $40 to buy. Pressure and voltage specs close enough too.


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## doanster (Apr 3, 2018)

I have been back and forth with Delavan all day. been explaining all the symptoms and providing information. I think they were starting to lean towards aftermarket Teejet nozzles as a possible culprit but i showed them that the stock fanjet nozzles from Chapin are almost identical to the teejet xr1104 nozzles.


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## gene_stl (Oct 29, 2017)

How could the nozzles cause that anyway. :roll: :evil:

If the wand trigger is closed the pump doesn't even see the nozzles.


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## doanster (Apr 3, 2018)

friend of mine has a chapin 20v sprayer as well and has had similar problem - so he brought it over to look at - looks almost identical on the outside - took the switch / battery housing cover off - the pump is not marked delavan like the other but looks the same - the inlet connection has a hard line with a snap clip instead of a clamp - the pressure switch is completely different - switch uses spade connectors, appears to be centered on diaphram (does not come apart). 2 sprayers by the same company - identical on the outside - but some major differences on the inside. spade connectors an pressure switch where loose - tightened them up - still waiting for a response from delevan - i asked them this question " if pump is similar to there powerflow 2200 - is there a better pressure switch available? can i bypass the pressure switch and use a mechanical pressure regulator inline?" hope to get a response soon.


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## doanster (Apr 3, 2018)

Have resolved the issue and made some other interesting discoveries - going to do a new post with that information.


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