User Tag List

Results 1 to 10 of 10
  1. #1
    New Member
    Join Date
    Nov 2019
    Location
    Texas
    Posts
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Hydraulic vs Electric Through Frame Slide-out System

    I recently traded in my 2015 Reflection 303RLS and purchased a 2021 Solitude 345GKR.

    Both units have LCI through frame rack and pinion systems with the major difference being the 303RLS was electric and the 345GKR is hydraulic.

    On the 303 (while both extending and retracting the slide) as the slide reach its limit a clutch system would engage and produce a "click, click, click" noise where I would release the slide switch as quickly as possible.

    I was expecting the same click on my 345GKR, but it's not there for sure. I do hear a slight change in hydraulic pump pitch as the slides are full extended or retracted, which is when I quickly release the slide switch.

    Looked around in search and on google and could not find if this is the intended operation or not.

    Do any of you with hydraulic through frame slide-out systems also have the clutch / click sounds?

    CC

  2. #2
    Site Sponsor JCR GD's Avatar
    Join Date
    Mar 2015
    Location
    Central Cal
    Posts
    3,248
    Mentioned
    16 Post(s)
    Tagged
    0 Thread(s)
    No clicking with hydraulic, just change in pitch.

    Edit: I don't know if even the electric is supposed to click. I do know that when cable driven slides are clicking they are striping gears.
    Last edited by JCR GD; 06-16-2021 at 12:51 PM.
    Jim (& Sharon)
    2015 GD Momentum 385TH - SOLD
    SOLD - 2015 Ford F-350 DRW 4x4 Lariat w/ AirLift bags, Titan 65 gal. OEM replacement fuel tank.
    The toy:
    2017 RZR XP 1000 EPS SE

  3. #3
    New Member
    Join Date
    Nov 2019
    Location
    Texas
    Posts
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by JCR GD View Post
    No clicking with hydraulic, just change in pitch.
    Outstanding! Thank you.
    2014 303RLS (Retired)
    2021 345GKR
    2018 RAM 3500 LB SRW
    CURT Q24 w/RAM 5th Wheel Prep

  4. #4
    Setting Up Camp
    Join Date
    Jul 2021
    Location
    Sonoma County, CA
    Posts
    30
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by heliguy71 View Post
    I recently traded in my 2015 Reflection 303RLS and purchased a 2021 Solitude 345GKR.

    Both units have LCI through frame rack and pinion systems with the major difference being the 303RLS was electric and the 345GKR is hydraulic.

    On the 303 (while both extending and retracting the slide) as the slide reach its limit a clutch system would engage and produce a "click, click, click" noise where I would release the slide switch as quickly as possible.

    I was expecting the same click on my 345GKR, but it's not there for sure. I do hear a slight change in hydraulic pump pitch as the slides are full extended or retracted, which is when I quickly release the slide switch.

    Looked around in search and on google and could not find if this is the intended operation or not.

    Do any of you with hydraulic through frame slide-out systems also have the clutch / click sounds?

    CC
    You are correct that the mechanical slide systems have a torque limiting clutch that makes that sound when the slides are at their ends of travel.

    Most hydraulic systems limit the force on the slides through hydraulic pressure so when they hit the limits an over-pressure valve opens. So basically release the switch when they stop moving.
    2021 Solitude 310GK

  5. #5
    Site Team xrated's Avatar
    Join Date
    Feb 2019
    Location
    "Murvul", TN
    Posts
    3,703
    Mentioned
    144 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by PappaJohn View Post
    You are correct that the mechanical slide systems have a torque limiting clutch that makes that sound when the slides are at their ends of travel.

    Most hydraulic systems limit the force on the slides through hydraulic pressure so when they hit the limits an over-pressure valve opens. So basically release the switch when they stop moving.
    What is the source of information on your statement that is mentioned above. I've never seen anything in the electrical schematic that indicates there is some sort of pressure relief valve that does what you are saying it will do. I also have not seen anything that indicates that there is any type of "Mechanically operated" pressure relief valve, anywhere in the hydraulic plumbing circuit. In fact, when the hydraulic slides are at the end of their travel, either extended or retracted, that change in pitch sound that is being referenced is the hydraulic pump motor straining because of the the pressure going higher in the system because the cylinder(s) have reached their end of travel and the hydraulic system is in effect "dead heading". It is worth mentioning here that there are NO ELECTICAL limit switches involved in either the extend or retract travel of the slides.....it is all mechanical stops.

    It is also important to note here.....the hydraulic slide cylinders have a mechanical stop adjustment for the distance travelled by the slide room itself. If those are not adjusted properly, they will put undue pressure/strain on the slide room....either when it is retracted and/or when they are extended. It's probably worth a look at your slides and check to make sure that they are properly adjusted.
    Last edited by xrated; 07-07-2021 at 06:42 AM.
    2016 F350 CrewCab Dually
    2018 Momentum 394M...Heavily Modded!
    2023 Suzuki GSX-S1000 GT+
    Excessive Payload is a Wonderful Thing

    "If it ain't fast....It ain't Fun"

  6. #6
    Setting Up Camp
    Join Date
    Jul 2021
    Location
    Sonoma County, CA
    Posts
    30
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by xrated View Post
    What is the source of information on your statement that is mentioned above. I've never seen anything in the electrical schematic that indicates there is some sort of pressure relief valve that does what you are saying it will do. I also have not seen anything that indicates that there is any type of "Mechanically operated" pressure relief valve, anywhere in the hydraulic plumbing circuit. In fact, when the hydraulic slides are at the end of their travel, either extended or retracted, that change in pitch sound that is being referenced is the hydraulic pump motor straining because of the the pressure going higher in the system because the cylinder(s) have reached their end of travel and the hydraulic system is in effect "dead heading". It is worth mentioning here that there are NO ELECTICAL limit switches involved in either the extend or retract travel of the slides.....it is all mechanical stops.
    The source of my information comes from years of working on hydraulic systems and my comment was “most hydraulic systems”. A hydraulic pressure relief valve would not be shown on an electrical schematic since electricity is not involved. The relief bypass valve is normally within the pump itself and limits the maximum pressure out of the pump. The relief valve would be set at a pressure higher than the max normally required to move the slides but below what could cause damage to the system. These valves are simple things often just a ball held into a seat by a spring and the pressure is set by selecting the proper spring force.

    Most pumps are or nearly are positive displacement pumps. If there wasn’t a pressure relief valve you would hear the pump motor stall when the slides hit the mechanical stops instead of the sound you reference of the motor working harder because of the hydraulic pressure has increased to the limit of the relief valve.
    2021 Solitude 310GK

  7. #7
    Site Team xrated's Avatar
    Join Date
    Feb 2019
    Location
    "Murvul", TN
    Posts
    3,703
    Mentioned
    144 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by PappaJohn View Post
    The source of my information comes from years of working on hydraulic systems and my comment was “most hydraulic systems”. A hydraulic pressure relief valve would not be shown on an electrical schematic since electricity is not involved. The relief bypass valve is normally within the pump itself and limits the maximum pressure out of the pump. The relief valve would be set at a pressure higher than the max normally required to move the slides but below what could cause damage to the system. These valves are simple things often just a ball held into a seat by a spring and the pressure is set by selecting the proper spring force.

    Most pumps are or nearly are positive displacement pumps. If there wasn’t a pressure relief valve you would hear the pump motor stall when the slides hit the mechanical stops instead of the sound you reference of the motor working harder because of the hydraulic pressure has increased to the limit of the relief valve.
    Thank you for that explanation....I totally understand what you are saying. I spent a lot of years working as a Journeyman Maint. Electrician in a Steel mill and we dealt with the electrical end of the various hydraulic systems....the actual pump motors, pressure switches if they were electrical pressure switches, electrically operated bypass valves in the hydraulic system, and of course all the control components and such that made the system work. So let me ask a hypothetical question here. Let's say the slide had reached the end of it's travel and the hydraulic cylinder was at the end of it's stroke (either extended or retracted) and you continued to hold the switch down as if you were wanting to continue to run the hydraulics. The fact that you can hear the motor groaning and obviously pulling more current than normal (when the slides are moving)....is an indication to you that there is in fact an internal bypass or relief bypass in the pump circuit...and likely in the pump itself....am I understanding that correctly. If there were no bypass or relief, would the motor stop running almost immediately as the head pressure would build quickly? I guess the most likely scenario if all that happened is the armature current would almost instantly go sky high as it would then be basically stalled, and the 80A breaker that feed the hydraulic pump would trip........or worst case scenario, a line or fitting rupture and you have a blown out hydraulic system.
    2016 F350 CrewCab Dually
    2018 Momentum 394M...Heavily Modded!
    2023 Suzuki GSX-S1000 GT+
    Excessive Payload is a Wonderful Thing

    "If it ain't fast....It ain't Fun"

  8. #8
    Setting Up Camp
    Join Date
    Jul 2021
    Location
    Sonoma County, CA
    Posts
    30
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by xrated View Post
    Thank you for that explanation....I totally understand what you are saying. I spent a lot of years working as a Journeyman Maint. Electrician in a Steel mill and we dealt with the electrical end of the various hydraulic systems....the actual pump motors, pressure switches if they were electrical pressure switches, electrically operated bypass valves in the hydraulic system, and of course all the control components and such that made the system work. So let me ask a hypothetical question here. Let's say the slide had reached the end of it's travel and the hydraulic cylinder was at the end of it's stroke (either extended or retracted) and you continued to hold the switch down as if you were wanting to continue to run the hydraulics. The fact that you can hear the motor groaning and obviously pulling more current than normal (when the slides are moving)....is an indication to you that there is in fact an internal bypass or relief bypass in the pump circuit...and likely in the pump itself....am I understanding that correctly. If there were no bypass or relief, would the motor stop running almost immediately as the head pressure would build quickly? I guess the most likely scenario if all that happened is the armature current would almost instantly go sky high as it would then be basically stalled, and the 80A breaker that feed the hydraulic pump would trip........or worst case scenario, a line or fitting rupture and you have a blown out hydraulic system.
    Your understanding is correct since the pumps are positive displacement and would stall the motor. Many of these pump motors are “series wound” like the starter motor in your car. These motors are designed to deliver a lot of torque and have a huge current when stalled. The motors would probably overheat if one held the switch for a long time after the slides were at their end stops.

    As I said I am basing this on past experience and not specific information about the LCI system. I was a factory trained repair station for HWH hydraulic leveling and slide systems and have been around hydraulics all my life. I’m pretty sure this is how the LCI system operates.
    2021 Solitude 310GK

  9. #9
    Site Team xrated's Avatar
    Join Date
    Feb 2019
    Location
    "Murvul", TN
    Posts
    3,703
    Mentioned
    144 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by PappaJohn View Post
    Your understanding is correct since the pumps are positive displacement and would stall the motor. Many of these pump motors are “series wound” like the starter motor in your car. These motors are designed to deliver a lot of torque and have a huge current when stalled. The motors would probably overheat if one held the switch for a long time after the slides were at their end stops.

    As I said I am basing this on past experience and not specific information about the LCI system. I was a factory trained repair station for HWH hydraulic leveling and slide systems and have been around hydraulics all my life. I’m pretty sure this is how the LCI system operates.
    Yep, very, very familiar with series wound DC motors. Of the three types of DC motors, the series wound, the shunt wound, and the compound wound, the Series wound motor will produce the most torque of the three....which is obviously what you want if that motor is powering a hydraulic pump. It's not great for speed control, but torque....yep, that's the one to use. Almost all of our overhead cranes were 250VDC and I have a wealth of experience troubleshooting and repairing them. Our biggest cranes, and we had 6 of them, were 400 Ton capacity on the main hoist and they were used to pick up ladles of molten steel. Two big Westinghouse MC618 Series wound motors and they would pull around 2500 amps when hoisting up a ladle. Anyway....I'm getting way off topic with my past life. Just suffice to say, I'm quite familiar with series wound motors. It was good getting info from you, as you are obviously a lot more knowledgeable about the hydraulic end of it than I am, so I appreciate your input greatly.
    2016 F350 CrewCab Dually
    2018 Momentum 394M...Heavily Modded!
    2023 Suzuki GSX-S1000 GT+
    Excessive Payload is a Wonderful Thing

    "If it ain't fast....It ain't Fun"

  10. #10
    Seasoned Camper
    Join Date
    Dec 2019
    Posts
    180
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Images from a PDF I wrote.. first image is Hi pressure cutoff switch. Second image is front control module that receives signal from hi pressure switch

    Lippert six point hyd system. The pressure switch is in play when hyd leveling legs are being operated AND hyd slide outs being operated
    Attached Thumbnails Attached Thumbnails AF351C9A-5BA9-46AD-A081-37AB0422DE1C.jpg   458CD24D-A714-488D-93AF-64B435E95152.jpg  

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

DISCLAIMER:This website is not affiliated with or endorsed by Grand Design RV, LLC or any of its affiliates. This is an independent site.