# Maximum Iteration exceeded error **URL:** \ **Category:** Thermal\ **Created:** [November 17, 2022, 7:00pm UTC](https://www.simscale.com/forum/t/maximum-iteration-exceeded-error/96372 "2022-11-17T19:00:29Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Msaheli19](https://www.simscale.com/forum/letter_avatar/msaheli19/32/6_22734026db12803ebb3e059622ac3534.png) [@Msaheli19](https://www.simscale.com/forum/u/Msaheli19)\ **Post date:** [November 17, 2022, 7:00pm UTC](https://www.simscale.com/forum/t/maximum-iteration-exceeded-error/96372/1 "2022-11-17T19:00:29Z")
I’ve been designing a concentric crossflow exhaust gas heat exchanger and I am getting the following error whenever I try to run the model. "Maximum number of iterations exceeded when calculating temperature from a thermodynamic potential. " My mesh appears to be fine but I may be missing something, I realize the temperature difference is large but when I did the calculations on it by hand it should still give me an answer. here is my project for reference: > **[SimScale Login](https://www.simscale.com/workbench/?pid=317842104402366344&mi=spec%3Ad76c8e72-71e6-47d3-930b-89fb98a4a48a%2Cservice%3ASIMULATION%2Cstrategy%3A13)** > > Log in to your SimScale account. SimScale makes high-fidelity engineering simulation technically and economically accessible. At any scale. In the cloud. ---
**Author:** ![ggiraldof](https://www.simscale.com/forum/user_avatar/www.simscale.com/ggiraldof/32/30298_2.png) [@ggiraldof](https://www.simscale.com/forum/u/ggiraldof)\ **Post date:** [November 17, 2022, 8:11pm UTC](https://www.simscale.com/forum/t/maximum-iteration-exceeded-error/96372/2 "2022-11-17T20:11:33Z")
Hi there! Did you already try the suggestions given in this page? > **[Error: Maximum Number of Iterations Exceeded | SimScale](https://www.simscale.com/knowledge-base/iterations-exceeded/)** > > In this documentation page, we will go through some common troubleshooting practices for the maximum number of iterations exceeded error. If you did, please let me know what you tried so my investigation is easier and faster! ---
**Author:** ![Msaheli19](https://www.simscale.com/forum/letter_avatar/msaheli19/32/6_22734026db12803ebb3e059622ac3534.png) [@Msaheli19](https://www.simscale.com/forum/u/Msaheli19)\ **Post date:** [November 20, 2022, 2:42pm UTC](https://www.simscale.com/forum/t/maximum-iteration-exceeded-error/96372/3 "2022-11-20T14:42:08Z")
Hello there, I have made the following changes: 1. Changed my geometries to have much smaller velocities 2. Used a level 8 fine mesh 3. Made sure that the fluid equations were correct. and I still am getting the same error Here is my updated version: [https://www.simscale.com/workbench/?pid=317842104402366344&mi=spec%3A71ac3962-de9b-4c2d-a1a7-302f0ec71b08%2Cservice%3AMESHING%2Cstrategy%3A24&sh=23](https://www.simscale.com/workbench/?pid=317842104402366344&mi=spec%3A71ac3962-de9b-4c2d-a1a7-302f0ec71b08%2Cservice%3AMESHING%2Cstrategy%3A24&sh=23) ---
**Author:** ![ggiraldof](https://www.simscale.com/forum/user_avatar/www.simscale.com/ggiraldof/32/30298_2.png) [@ggiraldof](https://www.simscale.com/forum/u/ggiraldof)\ **Post date:** [November 21, 2022, 3:04pm UTC](https://www.simscale.com/forum/t/maximum-iteration-exceeded-error/96372/4 "2022-11-21T15:04:50Z")
Hi, and thanks for your reply. I am suspicious if your “Galden HT230” material. Did you double check the properties? Have you used them before? ---
**Author:** ![Msaheli19](https://www.simscale.com/forum/letter_avatar/msaheli19/32/6_22734026db12803ebb3e059622ac3534.png) [@Msaheli19](https://www.simscale.com/forum/u/Msaheli19)\ **Post date:** [November 21, 2022, 10:07pm UTC](https://www.simscale.com/forum/t/maximum-iteration-exceeded-error/96372/5 "2022-11-21T22:07:39Z")
Ya I checked the properties and fixed the dynamic viscosity. ![image](https://www.simscale.com/forum/uploads/default/original/3X/2/f/2f69d5f446abf3740e0f3095d6c0731224cdd21a.jpeg) Here are the properties of this specific oil (2nd to last column) Here is my new simulation but it still gives the same error. > **[SimScale Login](https://www.simscale.com/workbench/?pid=317842104402366344&mi=run%3A27%2Csimulation%3A23&mt=SIMULATION_RUN)** > > Log in to your SimScale account. SimScale makes high-fidelity engineering simulation technically and economically accessible. At any scale. In the cloud. ---
**Author:** ![RicardoParis](https://www.simscale.com/forum/user_avatar/www.simscale.com/ricardoparis/32/30222_2.png) [@RicardoParis](https://www.simscale.com/forum/u/RicardoParis)\ **Post date:** [November 22, 2022, 2:25pm UTC](https://www.simscale.com/forum/t/maximum-iteration-exceeded-error/96372/6 "2022-11-22T14:25:42Z")
Hello, From having a look at the solver log, the simulation fails because one of the flow regions reaches negative temperatures: ![image](https://www.simscale.com/forum/uploads/default/original/3X/b/1/b114054b5ffacfe3a92de42d0c8592ee228555e7.png) This is likely related to some faces that are unnecessarily complex for the third flow region: ![image](https://www.simscale.com/forum/uploads/default/original/3X/2/c/2c678738190424539efb12f15aceab0922a27543.jpeg) You may find these faces close to the inlet and outlet faces of the air domain. I’d suggest cleaning up the CAD model around those regions. See this thread for more info: [Most Common CAD Issues with an Example](https://www.simscale.com/forum/t/most-common-cad-issues-with-an-example/96356) Cheers ---
**Author:** ![Msaheli19](https://www.simscale.com/forum/letter_avatar/msaheli19/32/6_22734026db12803ebb3e059622ac3534.png) [@Msaheli19](https://www.simscale.com/forum/u/Msaheli19)\ **Post date:** [November 23, 2022, 12:16am UTC](https://www.simscale.com/forum/t/maximum-iteration-exceeded-error/96372/7 "2022-11-23T00:16:48Z")
Appreciate the advice! Would you say that using the delete gap and face tool in CAD mode would be enough or do I have to go back and adjust the original model (adding fillets etc…).